JP6855012B2 - Measuring equipment, lithography systems, and device manufacturing methods - Google Patents

Description

The present invention relates to a measuring device, a lithography system, and a device manufacturing method, and in particular, a measuring device that measures the position information of a plurality of marks formed on a substrate, and the measurement of the position information of a plurality of marks by the measuring device is completed. The present invention relates to a lithography system including an exposure apparatus having a substrate stage on which a substrate is placed and the measuring apparatus, and a device manufacturing method using the lithography system.

In a lithography process for manufacturing a semiconductor element or the like, a multilayer circuit pattern is formed by superimposing a multilayer circuit pattern on a substrate such as a wafer or a glass plate (hereinafter, collectively referred to as a wafer). A semiconductor element or the like cannot exhibit a predetermined circuit characteristic, and in some cases, it becomes a defective product. Therefore, usually, a mark (alignment mark) is formed in advance in each of a plurality of shot regions on the wafer, and the position (coordinate value) of the mark on the stage coordinate system of the exposure apparatus is detected. After that, based on this mark position information and the known position information of the newly formed pattern (for example, a reticle pattern), wafer alignment is performed to align one shot area on the wafer with respect to the pattern. ..

As a wafer alignment method, an alignment mark of only some shot areas (also called a sample shot area or an alignment shot area) on the wafer is detected in consideration of throughput, and the arrangement of the shot areas on the wafer is a statistical method. Enhanced Global Alignment (EGA) calculated in is the mainstream.

However, in the lithography process, when overlay exposure is performed on a wafer, the wafer has undergone process processing processes such as resist coating, development, etching, CVD (chemical vapor deposition), and CMP (chemical mechanical polishing). The process may cause distortion in the arrangement of the shot region of the previous layer, and the distortion can cause a decrease in overlay accuracy. In view of this point, the recent exposure apparatus has a grid correction function for correcting not only the primary component of the wafer but also the non-linear component of the shot array caused by the process (see, for example, Patent Document 1). ).

However, with the miniaturization of integrated circuits, the requirement for overlay accuracy is becoming stricter, and in order to perform more accurate correction, it is necessary to increase the number of sample shot areas, that is, increase the number of marks to be detected. It is indispensable. Further, in a twin-stage type exposure apparatus provided with two stages on which a wafer is placed, the mark on the wafer is displayed on the other stage in parallel with the exposure of the wafer on one stage. Since detection and the like can be executed, it is possible to increase the number of sample shot regions without reducing the throughput as much as possible.

However, the requirements for overlay accuracy are now even more stringent, and even twin-stage type exposure equipment has a sufficient number of marks to achieve the required overlay accuracy without reducing throughput. Has become difficult to detect.

US Application Publication No. 2002/0042664

According to the first aspect, it is a measuring device that measures the position information of the mark formed on the substrate, the mark detection system for detecting the mark formed on the substrate, and the substrate can be held and moved. The stage, the base member that movably supports the stage, the first position measurement system that acquires the position information of the stage with respect to the base member, and the relative position information between the base member and the mark detection system are acquired. A second position measurement system and a detection system for acquiring height information of the substrate surface held on the stage are provided, and the position information of the stage acquired by the first position measurement system and the second position are provided. A measuring device for acquiring the position information of the mark based on the relative position information acquired by the measurement system and the mark detection result detected by the mark detection system is provided.

According to the second aspect, the substrate stage includes a measuring device according to the first aspect, and a substrate stage on which the substrate on which the measurement of the position information of the plurality of marks by the measuring apparatus has been completed is placed. An exposure in which alignment measurement for measuring the position information of a part of a plurality of marks selected from a plurality of marks on the substrate and exposure for exposing the substrate with an energy beam are performed on the substrate placed on the substrate. A lithography system comprising an apparatus is provided.

According to the third aspect, device manufacturing including exposing and developing a substrate using the lithography system according to the second aspect, and dividing the substrate on which a device pattern is formed into a plurality of chips. The method is provided.

It is a perspective view which shows typically the structure of the measuring apparatus which concerns on 1st Embodiment. FIG. 2A is a front view (viewed from the −Y direction) in which a part of the measuring device of FIG. 1 is omitted, and FIG. 2B is a cross section taken along an XZ plane passing through the optical axis AX1 of the mark detection system. It is sectional drawing which partially omitted the measuring apparatus. It is sectional drawing which partially omitted the measuring apparatus which cross-sectioned in the YZ plane passing through the optical axis AX1 of a mark detection system. FIG. 4A is a perspective view showing the head portion of the first position measurement system, and FIG. 4B is a plan view (viewed from the + Z direction) of the head portion of the first position measurement system. It is a figure for demonstrating the structure of the 2nd position measurement system. It is a block diagram which shows the input / output relation of the control apparatus which mainly constitutes the control system of the measurement apparatus which concerns on 1st Embodiment. It is a flowchart corresponding to the processing algorithm of the control device at the time of processing 1 lot of wafers. It is a figure which shows schematic the whole structure of the lithography system which concerns on 2nd Embodiment. It is a figure which shows schematic structure of the exposure apparatus shown in FIG. It is a block diagram which shows the input / output relation of the exposure control apparatus provided in the exposure apparatus. It is a figure which shows schematic the whole structure of the lithography system which concerns on a modification.

<< First Embodiment >>
Hereinafter, the first embodiment will be described with reference to FIGS. 1 to 7. FIG. 1 schematically shows the configuration of the measuring device 100 according to the first embodiment in a perspective view. The measuring device 100 shown in FIG. 1 is actually composed of a chamber and a component portion housed inside the chamber, but in the present embodiment, the description of the chamber will be omitted. In the present embodiment, the mark detection system MDS is provided as described later. In the following, the direction of the optical axis AX1 of the mark detection system MDS is the Z-axis direction, and a movable stage described later is provided in a plane orthogonal to the Z-axis direction. The direction in which is moved in a long stroke is the Y-axis direction, the direction orthogonal to the Z-axis and the Y-axis is the X-axis direction, and the rotation (tilt) directions around the X-axis, Y-axis, and Z-axis are θx, θy, and θz, respectively. The direction will be explained. Here, the mark detection system MDS has an L-shaped outer shape when viewed from the side (for example, when viewed from the + X direction), and a cylindrical lens barrel portion 41 is provided at the lower end (tip) thereof, and the lens barrel portion 41 is provided. Inside, an optical system (refractive optical system) composed of a plurality of lens elements having an optical axis AX1 in the Z-axis direction is housed. In this specification, for convenience of explanation, the optical axis AX1 of the refractive optics system inside the lens barrel portion 41 is referred to as the optical axis AX1 of the mark detection system MDS.

FIG. 2 (A) shows a front view (viewed from the −Y direction) of the measuring device 100 of FIG. 1 partially omitted, and FIG. 2 (B) shows an XZ plane passing through the optical axis AX1. The cross-sectional view of the measuring device 100 cross-sectionald in is shown with some omissions. Further, FIG. 3 shows a cross-sectional view of the measuring device 100 cross-sectionald in a YZ plane passing through the optical axis AX1 with a part omitted.

As shown in FIG. 1, the measuring device 100 has a platen 12 having an upper surface substantially parallel to the XY plane orthogonal to the optical axis AX1 and a platen 12 arranged on the platen 12 and holding the wafer W. A wafer slider (hereinafter abbreviated as slider) 10 that can move in the X-axis and Y-axis directions with a predetermined stroke and can move minutely (small displacement) in the Z-axis, θx, θy, and θz directions, and a slider. The drive system 20 for driving 10 (not shown in FIG. 1, see FIG. 6) and the X-axis, Y-axis, Z-axis, θx, θy, and θz directions of the slider 10 with respect to the platen 12 (hereinafter, 6 degrees of freedom). The first position measurement system 30 (not shown in FIG. 1, see FIGS. 3 and 6) for measuring the position information of the direction) and the mark on the wafer W mounted (held) on the slider 10 are marked. A second position measurement system 50 that measures the relative position information between the measurement unit 40 having the mark detection system MDS to be detected, the mark detection system MDS (measurement unit 40), and the platen 12 (not shown in FIG. 1, FIG. 6) and while controlling the drive of the slider 10 by the drive system 20, the measurement information by the first position measurement system 30 and the measurement information by the second position measurement system 50 are acquired, and the slider 10 is acquired by using the mark detection system MDS. A control device 60 (not shown in FIG. 1, see FIG. 6) for obtaining position information of a plurality of marks on the wafer W held on the wafer W is provided.

The surface plate 12 is made of a rectangular parallelepiped member having a rectangular shape (or a square) in a plan view, and its upper surface is finished so as to have a very high flatness, and a guide surface for moving the slider 10 is formed. As the material of the surface plate 12, a material having a low coefficient of thermal expansion, which is also called a zero expansion material, for example, an Invar type alloy, an ultra-low expansion cast steel, an ultra-low expansion glass ceramic, or the like is used.

The surface plate 12 has a notch shape with a bottom opening at one location in the center of the surface on the -Y side in the X-axis direction and one location at both ends of the surface on the + Y side in the X-axis direction, for a total of three locations. The vacant space 12a is formed. In FIG. 1, of the three vacant spaces 12a, the vacant space 12a formed on the surface on the −Y side is shown. A vibration isolator 14 is arranged inside each of the vacant spaces 12a. The surface plate 12 is supported at three points by three vibration isolators 14 on the upper surface parallel to the XY plane of the rectangular base frame 16 in a plan view installed on the floor F so that the upper surface is substantially parallel to the XY plane. Has been done. The number of vibration isolators 14 is not limited to three.

As shown in FIG. 3, the slider 10 has one aerial static pressure bearing (air bearing) 18 at each of the four corners of the bottom surface, for a total of four, and each bearing surface is substantially the same as the lower surface of the slider 10. Static pressure (intra-gap pressure) between the bearing surface of the pressurized air ejected from these four air bearings 18 toward the surface plate 12 and the upper surface (guide surface) of the surface plate 12. The slider 10 is floated and supported on the upper surface of the surface plate 12 via a predetermined clearance (gap, gap), for example, a clearance of about several μm. In the present embodiment, the slider 10 is made of zero-expandable glass (for example, Zerodur manufactured by Schott AG), which is a kind of zero-expandable material.

A concave portion 10a having a predetermined depth in a circular shape in a plan view having an inner diameter slightly larger than the diameter of the wafer W is formed on the upper portion of the slider 10, and a wafer holder WH having a diameter substantially the same as the diameter of the wafer W is arranged inside the concave portion 10a. ing. As the wafer holder WH, a vacuum chuck, an electrostatic chuck, a mechanical chuck, or the like can be used, but as an example, a pin chuck type vacuum chuck is used. The wafer W is sucked and held by the wafer holder WH in a state where the upper surface thereof is substantially the same as the upper surface of the slider 10. A plurality of suction ports are formed in the wafer holder WH, and the plurality of suction ports are connected to the vacuum pump 11 (see FIG. 6) via a vacuum piping system (not shown). Then, the on / off of the vacuum pump 11 and the like are controlled by the control device 60. In addition, either one or both of the slider 10 and the wafer holder WH may be referred to as a "first substrate holding member".

Further, the slider 10 moves up and down through, for example, three circular openings formed in the wafer holder WH, and moves the wafer on the wafer holder WH in cooperation with the wafer transfer system 70 (not shown in FIG. 1, see FIG. 6). A vertical moving member (not shown) is provided to load the wafer and unload the wafer from the wafer holder WH. The drive device 13 that drives the vertical movement member is controlled by the control device 60 (see FIG. 6).

In the present embodiment, it is assumed that, as an example, a wafer holder WH having a size capable of adsorbing and holding a 300 mm wafer having a diameter of 300 mm is used. When the wafer transfer system 70 has a non-contact holding member for sucking and holding the wafer on the wafer holder WH from above, for example, a Bernoulli chuck, it is necessary to provide a vertical movement member on the slider 10. Therefore, it is not necessary to form a circular opening for the vertical movement member in the wafer holder WH.

As shown in FIGS. 2B and 3, a two-dimensional grating (hereinafter, simply referred to as a grating) RG1 is horizontal (parallel to the wafer W surface) in a region one size larger than the wafer W on the lower surface of the slider 10. ) Is placed. The grating RG1 includes a reflection type diffraction grating (X diffraction grating) whose periodic direction is the X-axis direction and a reflection type diffraction grating (Y diffraction grating) whose periodic direction is the Y-axis direction. The pitch of the grid lines of the X diffraction grating and the Y diffraction grating is set to, for example, 1 μm.

The vibration isolator 14 is an active vibration isolation system (so-called AVIS (Active Vibration Isolation System)), and includes an accelerometer, a displacement sensor (for example, a capacitance sensor), an actuator (for example, a voice coil motor), and an air damper. It is equipped with an air mount that functions as a function. The vibration isolator 14 can dampen relatively high-frequency vibrations by an air mount (air damper), and can also vibration isolation (vibration control) by an actuator. Therefore, the vibration isolator 14 can avoid transmission of vibration between the surface plate 12 and the base frame 16. A hydraulic damper may be used instead of the air mount (air damper).

Here, the actuator is provided in addition to the air mount because the internal pressure of the gas in the gas chamber of the air mount is high and the control response can be secured only about 20 Hz. Therefore, when high response control is required, This is because it is necessary to control the actuator according to the output of an accelerometer (not shown). However, slight vibrations such as floor vibrations are eliminated by the air mount.

The upper end surface of the vibration isolator 14 is connected to the surface plate 12. Gas (for example, compressed air) can be supplied to the air mount through a gas supply port (not shown), and the air mount responds to the amount of gas filled inside (change in pressure of compressed air). It expands and contracts in the Z-axis direction with a predetermined stroke (for example, about 1 mm). Therefore, by using the air mounts of the three vibration isolators 14 to move the surface plate 12 up and down individually from below, the surface plate 12 and the slider 10 floatingly supported on the surface plate 12 are moved to Z. The positions of the axial direction, the θx direction, and the θy direction can be arbitrarily adjusted. Further, the actuator of the vibration isolator 14 can drive the surface plate 12 not only in the Z-axis direction but also in the X-axis direction and the Y-axis direction. The drive amount in the X-axis direction and the Y-axis direction is smaller than the drive amount in the Z-axis direction. The three vibration isolation devices 14 are connected to the control device 60 (see FIG. 6). Each of the three vibration isolation devices 14 may be provided with an actuator capable of moving the surface plate 12 in, for example, 6 degrees of freedom direction, not limited to the X-axis direction, the Y-axis direction, and the Z-axis direction. The control device 60 is the head portion of the first position measurement system 30, which will be described later, based on the relative position information between the mark detection system MDS (measurement unit 40) measured by the second position measurement system 50 and the surface plate 12. The actuators of the three vibration isolation devices 14 are constantly controlled in real time so that the position of the surface plate 12 to which the 32 is fixed in the direction of six degrees of freedom maintains a desired positional relationship with respect to the mark detection system MDS. .. Note that each of the three vibration isolation devices 14 may be feedforward controlled. For example, the control device 60 may feed-forward control each of the three vibration isolation devices 14 based on the measurement information of the first position measurement system 30. The control of the vibration isolator 14 by the control device 60 will be further described later.

As shown in FIG. 6, the drive system 20 includes a first drive device 20A that drives the slider 10 in the X-axis direction, and a second drive device 20A that drives the slider 10 integrally with the first drive device 20A in the Y-axis direction. Includes 20B.

As can be seen from FIGS. 1 and 3, a pair of inverted L-shaped movers 22a in the side view, which are composed of a magnet unit (or a coil unit), are predetermined on the side surface of the slider 10 on the −Y side in the X-axis direction. It is fixed at intervals. As shown in FIG. 3, a pair of movers 22b composed of magnet units (or coil units) (however, the movers 22b on the + X side are not shown) are placed on the + Y side of the slider 10 in the X-axis direction. It is fixed at regular intervals. The pair of movers 22a and the pair of movers 22b are arranged symmetrically, but are configured in the same manner as each other.

As shown in FIGS. 1 to 3, the movers 22a and 22b are arranged at a predetermined distance in the Y-axis direction forming a part of the movable stage 24 having a rectangular frame shape in a plan view, and extend in the X-axis direction, respectively. The pair of plate members 24a, 24b are non-contactly supported on the upper surface substantially parallel to the XY plane. That is, air bearings (not shown) are provided on the lower surfaces of the movers 22a and 22b (surfaces facing the plate members 24a and 24b, respectively), and these air bearings are generated with respect to the plate members 24a and 24b. The movers 22a and 22b are supported by the movable stage 24 from below in a non-contact manner by a levitation force (static pressure of pressurized air). The weight of the slider 10 to which each pair of movers 22a and 22b is fixed is supported by the levitation force generated by the four air bearings 18 on the surface plate 12 as described above.

As shown in FIGS. 1 to 3, on the upper surfaces of the pair of plate members 24a and 24b, stators 26a and 26b made of coil units (or magnet units) are formed in a region excluding both ends in the X-axis direction. Have been placed.

The driving force (electromagnetic force) that drives the pair of movers 22a in the X-axis direction and the driving force (electromagnetic force) that drives the pair of movers 22a in the Y-axis direction by the electromagnetic interaction between the pair of movers 22a and the stator 26a. Is generated, and due to the electromagnetic interaction between the pair of movers 22b and the stator 26b, the driving force (electromagnetic force) for driving the pair of movers 22b in the X-axis direction and the driving force for driving in the Y-axis direction are generated. (Electromagnetic force) is generated. That is, the pair of movers 22a and the stator 26a constitute an XY linear motor 28A that generates driving forces in the X-axis direction and the Y-axis direction, and the pair of movers 22b and the stator 26b constitute the XY linear motor 28A. An XY linear motor 28B that generates a driving force in the Y-axis direction is configured, and the slider 10 is driven by a predetermined stroke in the X-axis direction by the XY linear motor 28A and the XY linear motor 28B, and is minute in the Y-axis direction. The first driving device 20A to be driven is configured (see FIG. 6). The first drive device 20A can drive the slider 10 in the θz direction by making the magnitude of the driving force generated by the XY linear motor 28A and the XY linear motor 28B different in the X-axis direction. The first drive device 20A is controlled by the control device 60 (see FIG. 6). In the present embodiment, the first drive device 20A has a driving force in the X-axis direction because it constitutes a coarse and fine movement drive system that drives the slider 10 in the Y-axis direction by the first drive device 20A together with the second drive device described later. Not only that, a driving force in the Y-axis direction is also generated, but the first driving device 20A does not necessarily have to generate a driving force in the Y-axis direction.

The movable stage 24 has a pair of plate members 24a and 24b, and a pair of connecting members 24c and 24d arranged at a predetermined distance in the X-axis direction and extending in the Y-axis direction, respectively. Steps are formed at both ends of the connecting members 24c and 24d in the Y-axis direction. Then, the connecting members 24c and 24d and the plate member 24a are placed in a state where one end and the other end in the longitudinal direction of the plate member 24a are placed on the steps on the −Y side of each of the connecting members 24c and 24d. It is integrated. Further, the connecting members 24c and 24d and the plate member 24b are integrated in a state where one end and the other end in the longitudinal direction of the plate member 24b are placed on the step portions on the + Y side of each of the connecting members 24c and 24d. (See Fig. 2 (B)). That is, in this way, the pair of plate members 24a and 24b are connected by the pair of connecting members 24c and 24d to form the rectangular frame-shaped movable stage 24.

As shown in FIGS. 1 and 2A, a pair of linear guides 27a and 27b extending in the Y-axis direction are fixed in the vicinity of both ends of the upper surface of the base frame 16 in the X-axis direction. Inside one of the linear guides 27a located on the + X side, a stator of a Y-axis linear motor 29A composed of a coil unit (or magnet unit) extending over almost the entire length in the Y-axis direction near the upper surface and the surface on the −X side. 25a (see FIG. 2B) is stored. A magnet unit (or coil unit) having an L-shaped cross section is formed so as to face the upper surface of the linear guide 27a and the surface on the −X side, and the stator 23a and the mover 23a constituting the Y-axis linear motor 29A are arranged together with the stator 25a. ing. Air bearings that eject pressurized air to the facing surfaces are fixed to the lower surface of the mover 23a and the surface on the + X side, which face the upper surface of the linear guide 27a and the surface on the −X side, respectively. Among them, as the air bearing fixed to the + X side surface of the mover 23a, a vacuum preload type air bearing is used. This vacuum preload type air bearing is located between the mover 23a and the linear guide 27a due to the balance between the static pressure of the pressurized air between the bearing surface and the surface on the −X side of the linear guide 27a and the vacuum prepressure. Maintain the clearance (gap, gap) in the X-axis direction at a constant value.

On the upper surface of the mover 23a, a plurality of X guides 19 composed of, for example, two rectangular parallelepiped members are fixed at predetermined intervals in the Y-axis direction. A slide member 21 having an inverted U-shaped cross section, which constitutes a uniaxial guide device together with the X guide 19, is engaged with each of the two X guides 19 in a non-contact manner. Air bearings are provided on each of the three surfaces of the slide member 21 facing the X guide 19.

As shown in FIG. 1, the two slide members 21 are fixed to the lower surface (the surface on the −Z side) of the connecting member 24c, respectively.

The other linear guide 27b located on the −X side houses the stator 25b of the Y-axis linear motor 29B composed of a coil unit (or magnet unit) inside, and is symmetrical, but has the same configuration as the linear guide 27a. (See FIG. 2 (B)). It consists of a magnet unit (or coil unit) that is symmetrical but has an L-shaped cross section similar to the mover 23a, facing the upper surface of the linear guide 27b and the surface on the + X side, and together with the stator 25b, a Y-axis linear motor. The mover 23b constituting the 29B is arranged. Air bearings are fixed to the lower surface of the mover 23b and the surface on the -X side, respectively, facing the upper surface of the linear guide 27b and the surface on the + X side, and in particular, fixed to the surface on the -X side of the mover 23b. A vacuum preload type air bearing is used as the air bearing. By this vacuum preload type air bearing, the clearance (gap, gap) in the X-axis direction between the mover 23b and the linear guide 27b is maintained at a constant value.

Between the upper surface of the mover 23b and the bottom surface of the connecting member 24d, there are two uniaxial guide devices composed of the X guide 19 and the slide member 21 which engages with the X guide 19 in a non-contact manner, as described above. There are two.

The movable stage 24 is supported from below by the movers 23a and 23b via two uniaxial guide devices (four in total) on the + X side and the −X side, and is supported in the X-axis direction on the movers 23a and 23b. It is movable. Therefore, when the slider 10 is driven in the X-axis direction by the first driving device 20A described above, the reaction force of the driving force acts on the movable stage 24 provided with the stators 26a and 26b, and the movable stage 24 moves in the direction opposite to that of the slider 10 according to the law of conservation of momentum. That is, the generation of vibration caused by the reaction force of the driving force in the X-axis direction with respect to the slider 10 is prevented (or effectively suppressed) by the movement of the movable stage 24. That is, the movable stage 24 functions as a counter mass when the slider 10 moves in the X-axis direction. However, the movable stage 24 does not necessarily have to function as a counter mass. The slider 10 is not particularly provided because it only moves slightly in the Y-axis direction with respect to the movable stage 24, but vibration is generated due to the driving force for driving the slider 10 in the Y-axis direction with respect to the movable stage 24. A counter mass may be provided to prevent (or effectively suppress) the above.

The Y-axis linear motor 29A generates a driving force (electromagnetic force) that drives the mover 23a in the Y-axis direction by electromagnetic interaction between the mover 23a and the stator 25a, and the Y-axis linear motor 29B is movable. A driving force (electromagnetic force) that drives the mover 23b in the Y-axis direction is generated by an electromagnetic interaction between the child 23b and the stator 25b.

The driving force generated by the Y-axis linear motors 29A and 29B in the Y-axis direction acts on the movable stage 24 via two uniaxial guide devices on the + X side and the −X side. As a result, the slider 10 is driven in the Y-axis direction integrally with the movable stage 24. That is, in the present embodiment, the second drive device 20B (see FIG. 6) that drives the slider 10 in the Y-axis direction by the movable stage 24, the four uniaxial guide devices, and the pair of Y-axis linear motors 29A and 29B. Is configured.

In the present embodiment, the pair of Y-axis linear motors 29A and 29B are physically separated from the surface plate 12 and also vibrated by three vibration isolation devices 14. The linear guides 27a and 27b provided with the stators 25a and 25b of the pair of Y-axis linear motors 29A and 29B, respectively, are configured to be movable in the Y-axis direction with respect to the base frame 16, and the Y of the slider 10 is formed. It may function as a counter mass when driven in the axial direction.

As shown in FIG. 1, the measuring unit 40 has a unit body 42 in which a notched space 42a having an open bottom is formed on the surface on the −Y side, and a base end portion is inserted into the space 42a. It has the above-mentioned mark detection system MDS connected to the unit main body 42 in this state, and a connection mechanism 43 for connecting the lens barrel portion 41 at the tip of the mark detection system MDS to the unit main body 42.

The connection mechanism 43 has a support plate 44 that supports the lens barrel portion 41 on the back side (+ Y side) via a mounting member (not shown), and a unit body 42 that supports the support plate 44 at one end of each and the other end. Includes a pair of support arms 45a, 45b fixed to the bottom surface of the mirror.

In the present embodiment, a detection beam having a wavelength that does not expose the resist is used as the mark detection system MDS in response to the fact that the sensitive agent (resist) is applied to the upper surface of the wafer held on the slider 10. Is used. As a mark detection system MDS, for example, a broadband detection light beam that does not expose the resist coated on the wafer is irradiated to the target mark, and the image of the target mark imaged on the light receiving surface by the reflected light from the target mark is not visible. FIA (Field Image Alignment) system of image processing method that images the image of the indicated index (index pattern on the index plate provided inside) using an image sensor (CCD, etc.) and outputs those imaged signals. Is used. The image pickup signal from the mark detection system MDS is supplied to the control device 60 via the signal processing device 49 (not shown in FIG. 1, see FIG. 6) (see FIG. 6). The mark detection system MDS has an alignment autofocus function for adjusting the focal position of the optical system.

As shown in FIG. 1, a head mounting member 51 having a substantially isosceles triangle shape is arranged between the lens barrel portion 41 and the support plate 44. The head mounting member 51 is formed with an opening penetrating in the Y-axis direction of FIG. 1, and the lens barrel portion 41 is mounted on the support plate 44 via a mounting member (not shown) inserted into the opening. It is (fixed). The back surface of the head mounting member 51 is also fixed to the support plate 44. In this way, the lens barrel portion 41 (mark detection system MDS), the head mounting member 51, and the support plate 44 are integrated with the unit main body 42 via a pair of support arms 45a and 45b.

Inside the unit body 42, the above-mentioned signal processing device 49 or the like described above that processes an imaging signal output as a detection signal from the mark detection system MDS, calculates the position information of the target mark with respect to the detection center, and outputs the position information to the control device 60. Is placed. The unit main body 42 is supported at three points from below on a gate-shaped support frame 46 installed on the base frame 16 when viewed from the −Y side via a plurality of, for example, three vibration isolation devices 48. Each vibration isolator 48 is an active vibration isolation system (so-called AVIS (Active Vibration Isolation System)), and includes an accelerometer, a displacement sensor (for example, a capacitance sensor), an actuator (for example, a voice coil motor), and an actuator. A mechanical damper such as an air damper or a hydraulic damper is provided, and the vibration isolator 48 can dampen relatively high-frequency vibrations by the mechanical damper and also vibration-isolates (vibrates) by an actuator. be able to. Therefore, each vibration isolator 48 can prevent the vibration of a relatively high frequency from being transmitted between the support frame 46 and the unit main body 42.

The mark detection system MDS is not limited to the FIA system. For example, the target mark is irradiated with coherent detection light, and two diffracted lights (for example, diffracted light of the same order or diffracted in the same direction) generated from the target mark are diffracted. A diffracted light interference type alignment detection system that detects and outputs a detection signal by interfering with the diffracted light) may be used instead of the FIA system. Alternatively, a diffracted light interference type alignment system may be used together with the FIA system to detect two target marks at the same time. Further, as the mark detection system MDS, a beam scan type alignment system that scans the measurement light in the predetermined direction with respect to the target mark while moving the slider 10 in the predetermined direction may be used. Further, in the present embodiment, the mark detection system MDS is assumed to have an alignment autofocus function, but instead of or in addition to this, the measurement unit 40 is a focus position detection system, for example, the United States. A multipoint focal position detection system of an oblique incident type having the same configuration as that disclosed in Japanese Patent No. 5,448,332 may be provided.

As shown in FIGS. 2B and 3, the first position measurement system 30 has a head portion 32 arranged in a recess formed on the upper surface of the surface plate 12 and fixed to the surface plate 12. The upper surface of the head portion 32 faces the lower surface of the slider 10 (the forming surface of the grating RG1). A predetermined clearance (gap, gap), for example, a clearance of about several mm is formed between the upper surface of the head portion 32 and the lower surface of the slider 10.

As shown in FIG. 6, the first position measurement system 30 includes an encoder system 33 and a laser interferometer system 35. The encoder system 33 irradiates a plurality of beams from the head portion 32 to the measurement unit (forming surface of the grating RG1) on the lower surface of the slider 10, and a plurality of return beams (for example, the grating RG1) from the measurement unit on the lower surface of the slider 10. It is possible to acquire the position information of the slider 10 by receiving a light receiving a plurality of diffraction beams from the above. The encoder system 33 includes an X linear encoder 33x that measures the position of the slider 10 in the X-axis direction, and a pair of Y linear encoders 33ya and 33yb that measure the position of the slider 10 in the Y-axis direction. In the encoder system 33, for example, the encoder head disclosed in US Pat. No. 7,238,931 and US Patent Application Publication No. 2007 / 288, 121 (hereinafter, abbreviated as head as appropriate). A diffraction interference type head having a similar configuration is used. The head includes a light source, a light receiving system (including a photodetector), and an optical system. In the present embodiment, at least the optical system faces the grating RG1 and is inside the housing of the head portion 32. At least one of the light source and the light receiving system may be arranged outside the housing of the head portion 32.

FIG. 4 (A) shows the head portion 32 in a perspective view, and FIG. 4 (B) shows a plan view of the upper surface of the head portion 32 as viewed from the + Z direction. The encoder system 33 measures the position of the slider 10 in the X-axis direction with one X-head 37x, and measures the position in the Y-axis direction with a pair of Y-heads 37ya and 37yb (see FIG. 4B). That is, the above-mentioned X linear encoder 33x is configured by the X head 37x that measures the position of the slider 10 in the X-axis direction using the X diffraction grating of the grating RG1, and the Y of the slider 10 is used by using the Y diffraction grating of the grating RG1. A pair of Y linear encoders 33ya and 33yb are configured by a pair of Y heads 37ya and 37yb that measure the position in the axial direction.

As shown in FIGS. 4A and 4B, the X head 37x is parallel to the Y axis passing through the center of the head portion 32 on a straight line LX parallel to the X axis passing through the center of the head portion 32. From two points equidistant from the straight line CL (see the white circle in FIG. 4 (B)), the measurement beams LBx ₁ and LB x ₂ (shown by the solid line in FIG. 4 (A)) are projected on the grating RG1. Irradiate to the same irradiation point. The irradiation points of the measurement beams LBx ₁ and LBx ₂ , that is, the detection points of the X head 37x (see the code DP in FIG. 4B) are located at the detection centers of the mark detection system MDS in the X-axis direction and the Y-axis direction. Match.

Here, in the measurement beams LBx ₁ and LBx ₂ , the beam from the light source is polarized and separated by a polarizing beam splitter (not shown), and when the measurement beams LBx ₁ and LBx ₂ are irradiated on the grating RG1, these measurements are taken. A predetermined order diffracted by an X diffraction grating of beams LBx ₁ and LBx ₂ , for example, a first-order diffraction beam (first diffraction beam) is folded back by a reflection mirror via a lens (not shown) and a quarter-wave plate, respectively. By passing through the quarter-wave plate twice, the polarization direction is rotated by 90 degrees, and after passing through the original optical path and re-entering the polarizing beam splitter and being coaxially synthesized, the measurement beams LBx ₁ , LBx The position of the slider 10 in the X-axis direction is measured by receiving the interference light between the primary diffraction beams _{2 by a light detector (not shown).}

As shown in FIG. 4B, the pair of Y heads 37ya and 37yb are arranged on the + X side and the −X side of the straight line CL, respectively. As shown in FIGS. 4 (A) and 4 (B), the Y head 37ya is located on the grating RG1 from two points (see the white circle in FIG. 4 (B)) having the same distance from the straight line LX on the straight line LYa. The common irradiation points of the above are irradiated with the measurement beams LBya ₁ and LBya ₂ shown by the broken lines in FIG. 4 (A), respectively. The irradiation points of the measurement beams LBya ₁ and LBya ₂ , that is, the detection points of the Y head 37ya are indicated by the reference numerals DPya in FIG. 4 (B).

Y head 37yb is, about the line CL, measurement beams LBya _1, LBya two symmetrical points to the injection point of the _two Y heads 37ya (see open circles in FIG. 4 (B)), the measuring beam LByb _1, LByb _2, grating Irradiate the common irradiation point DPyb on RG1. As shown in FIG. 4B, the detection points DPya and DPyb of the Y heads 37ya and 37yb are arranged on a straight line LX parallel to the X axis.

The measurement beams LBya ₁ and LBya ₂ also have the same beam polarized and separated by a polarization beam splitter, and the measurement beams LBya ₁ and LBya _{2 have} a predetermined order according to the Y diffraction grating, for example, the first diffraction beam (second diffraction). The interference light between the beams) is photoelectrically detected by a photodetector (not shown) in the same manner as described above, so that the position of the slider 10 in the Y-axis direction is measured. For even measurement beams LByb _1, LByb _2, similarly to the measurement beams LBya _1, LBya _2, 1-order diffracted beam (the second diffraction beam) interference light each other, it is photoelectrically detected by the light detector (not shown) , The position of the slider 10 in the Y-axis direction is measured.

Here, the control device 60 determines the position of the slider 10 in the Y-axis direction based on the average of the measured values of the two Y heads 37ya and 37yb. Therefore, in the present embodiment, the position of the slider 10 in the Y-axis direction is measured with the detection points DPya and the midpoint DP of DPyb as substantial measurement points. The midpoint DP coincides with the irradiation point on the grating RG1 of the measurement beams LBx ₁ and LBX _2.

That is, in the present embodiment, the slider 10 has a common detection point for measuring the position information in the X-axis direction and the Y-axis direction, and this detection point is a position in the XY plane at the detection center of the mark detection system MDS. Three vibration isolation devices based on the relative position information between the mark detection system MDS (measurement unit 40) and the surface plate 12 measured by the second position measurement system 50 by the control device 60 so that 14 actuators are constantly controlled in real time. Therefore, in the present embodiment, the control device 60 uses the encoder system 33 to measure the position information of the slider 10 in the XY plane when measuring the alignment mark on the wafer W placed on the slider 10. Can always be performed immediately below the detection center of the mark detection system MDS (on the back surface side of the slider 10). Further, the control device 60 measures the amount of rotation of the slider 10 in the θz direction based on the difference between the measured values of the pair of Y heads 37ya and 37yb.

The laser interferometer 35 causes the length measuring beam to be incident on the measuring unit (the surface on which the grating RG1 is formed) on the lower surface of the slider 10 and emits the return beam (for example, the reflected light from the surface on which the grating RG1 is formed). The position information of the slider 10 can be acquired by receiving light. As shown in FIG. 4A, the laser interferometer system 35 has four length measuring beams LBz ₁ , LBz ₂ , LBz ₃ , and LBz ₄ on the lower surface of the slider 10 (the surface on which the grating RG1 is formed). To be incident on. The laser interferometer system 35 includes laser interferometers 35a to 35d (see FIG. 6) that irradiate each of _{these four length measuring beams LBz 1} , LBz ₂ , LBz ₃ , and LBz _4. In this embodiment, the laser interferometers 35a to 35d constitute four Z heads.

In the laser interferometer system 35, as shown in FIGS. 4 (A) and 4 (B), four length measuring beams LBz ₁ , LBz ₂ , LBz ₃ , and LBz ₄ are centered on the detection point DP. It is ejected parallel to the Z axis from four points corresponding to each vertex of a square having two sides parallel to the X axis and two sides parallel to the Y axis. In this case, the emission points (irradiation points) of the length measuring beams LBz ₁ and LBz ₄ are equidistant from the straight line LX on the straight line LYa, and the emission points (irradiation points) of the remaining length measuring beams LBz ₂ and LBz ₃ are. It is equidistant from the straight line LX on the straight line LYb. In the present embodiment, the surface on which the grating RG1 is formed also serves as the reflection surface of each length measuring beam from the laser interferometer system 35. The control device 60 uses the laser interferometer system 35 to measure information on the position of the slider 10 in the Z-axis direction and the amount of rotation in the θx and θy directions. As is clear from the above description, the slider 10 is not positively driven by the drive system 20 described above with respect to the surface plate 12 in each of the Z-axis, θx, and θy directions. Since the four air bearings 18 arranged at the four corners of the bottom surface are instructed to levitate on the surface plate 12, the slider 10 is actually mounted on the surface plate 12 in each of the Z-axis, θx and θy directions. The position changes. That is, the slider 10 is actually movable with respect to the surface plate 12 in each of the Z-axis, θx, and θy directions. In particular, the displacement of the slider 10 in each direction of θx and θy causes a measurement error (abbe error) of the encoder system 33. In consideration of this point, the position information of the slider 10 in each of the Z-axis, θx and θy directions is measured by the first position measurement system 30 (laser interferometer system 35).

In order to measure the information on the position of the slider 10 in the Z-axis direction and the amount of rotation in the θx and θy directions, it is sufficient if the beam can be incident on three different points on the surface on which the grating RG1 is formed. , Z heads, for example, laser interferometers may be three. A protective glass for protecting the grating RG1 is provided on the lower surface of the slider 10, and each measurement beam from the encoder system 33 is transmitted to the surface of the protective glass to transmit each measurement beam from the laser interferometer system 35. A wavelength selection filter may be provided to prevent it.

As can be seen from the above description, the control device 60 can measure the position of the slider 10 in the six degrees of freedom direction by using the encoder system 33 and the laser interferometer system 35 of the first position measurement system 30. In this case, in the encoder system 33, since the optical path length of the measurement beam in the air is extremely short and substantially equal, the influence of air fluctuation can be almost ignored. Therefore, the encoder system 33 can measure the position information of the slider 10 in the XY plane (including the θz direction) with high accuracy. Further, the detection points on the substantially grating RG1 in the X-axis direction and the Y-axis direction by the encoder system 33 and the detection points on the lower surface of the slider 10 in the Z-axis direction by the laser interferometer system 35 are the mark detection system MDS, respectively. Since the detection center coincides with the detection center in the XY plane, the occurrence of so-called abbet error due to the deviation between the detection point and the detection center of the mark detection system MDS in the XY plane is suppressed to a substantially negligible level. Therefore, by using the first position measurement system 30, the control device 60 does not have an abbe error due to a deviation in the XY plane between the detection point and the detection center of the mark detection system MDS, and the slider 10 is in the X-axis direction, Y. The positions in the axial direction and the Z-axis direction can be measured with high accuracy.

However, with respect to the Z-axis direction parallel to the optical axis AX1 of the mark detection system MDS, the position information of the slider 10 in the XY plane is not measured by the encoder system 33 at the position of the surface of the wafer W, that is, The Z positions of the arrangement surface of the grating RG1 and the surface of the wafer W do not match. Therefore, when the grating RG1 (that is, the slider 10) is tilted with respect to the XY plane, positioning the slider 10 based on the measurement value of each encoder of the encoder system 33 results in the arrangement surface of the grating RG1. Due to the difference ΔZ between the Z position and the surface of the wafer W (that is, the positional deviation in the Z-axis direction between the detection point by the encoder system 33 and the detection center (detection point) by the mark detection system MDS), the XY of the grating RG1 A positioning error (a kind of Abbe error) occurs according to the inclination with respect to the plane. However, this positioning error (position control error) can be obtained by a simple calculation using the difference ΔZ, the pitching amount θx, and the rolling amount θy. By positioning the slider 10 based on the corrected position information obtained by correcting the measured value of each encoder), the influence of the above-mentioned kind of Abbe error is eliminated. Alternatively, instead of correcting the measured values of the encoder system 33 (each encoder), one or more pieces of information for moving the slider, such as the target position where the slider 10 should be positioned, are corrected based on the above offset. You may.

When the grating RG1 (that is, the slider 10) is tilted with respect to the XY plane, the head portion 32 may be moved so that a positioning error due to the tilt does not occur. That is, when the first position measurement system 30 (for example, the interferometer system 35) measures that the grating RG1 (that is, the slider 10) is tilted with respect to the XY plane, the first position measurement system 30 The surface plate 12 holding the head portion 32 may be moved based on the position information acquired by using. As described above, the surface plate 12 can be moved by using the vibration isolator 14.

Further, when the grating RG1 (that is, the slider 10) is tilted with respect to the XY plane, the position information of the mark acquired by using the mark detection system MDS is corrected based on the positioning error caused by the tilt. Is also good.

As shown in FIGS. 1, 2 (A) and 2 (B), the second position measurement system 50 is provided on the lower surfaces of one end and the other end of the head mounting member 51 in the longitudinal direction, respectively. It has a pair of head portions 52A and 52B, and scale members 54A and 54B arranged to face the head portions 52A and 52B. The upper surfaces of the scale members 54A and 54B have the same height as the surface of the wafer W held by the wafer holder WH. Reflective two-dimensional gratings RG2a and RG2b are formed on the upper surfaces of the scale members 54A and 54B, respectively. Two-dimensional gratings (hereinafter abbreviated as gratings) RG2a and RG2b are both a reflection type diffraction grating (X diffraction grating) whose periodic direction is in the X-axis direction and a reflection type diffraction grating (X-diffraction grating) whose periodic direction is in the Y-axis direction. Y diffraction grating) and. The pitch of the grid lines of the X diffraction grating and the Y diffraction grating is set to, for example, 1 μm.

The scale members 54A and 54B are made of a material having a low coefficient of thermal expansion, for example, the zero expansion material described above, and as shown in FIGS. 2 (A) and 2 (B), the surface plate 12 is provided via the support member 56, respectively. It is fixed on top. In the present embodiment, the dimensions of the scale members 54A and 54B and the support member 56 are determined so that the gratings RG2a and RG2b and the head portions 52A and 52B face each other with a gap of about several mm.

As shown in FIG. 5, one head portion 52A fixed to the lower surface of the + X side end portion of the head mounting member 51 measures the X-axis and Z-axis directions housed inside the same housing. including the XZ head 58X ₁ to a direction, and a YZ head 58Y ₁ whose measurement direction in the Y-axis and Z-axis directions. The XZ head 58X ₁ (more accurately, the irradiation point on the grating RG2a of the measurement beam emitted by the _{XZ head 58X 1 ) and the YZ head 58Y 1} (more accurately, the two-dimensional grating of the measurement beam emitted by the _{YZ head 58Y 1).} The irradiation point on the RG2a) is arranged on a straight line parallel to the same Y-axis.

The other head portion 52B is arranged symmetrically with respect to the straight line (hereinafter referred to as the reference axis) LV parallel to the Y axis passing through the optical axis AX1 of the mark detection system MDS, but is the same as the head portion 52A. It is configured in. That is, the head portion 52B has an XZ head _58X 2, YZ heads 58Y ₂ arranged in XZ head _58X 1, YZ head 58Y ₁ and symmetrically with respect to reference axis LV, the XZ head _58X 2, YZ heads 58Y ₂ The irradiation points of the measurement beams irradiated on the grating RG2b from each are set on a straight line parallel to the same Y axis. Here, the reference axis LV coincides with the straight line CL described above.

As each of the XZ heads 58X ₁ and 58X ₂ and the YZ heads 58Y ₁ and 58Y ₂ , for example, an encoder head having the same configuration as the displacement measurement sensor head disclosed in US Pat. No. 7,561,280 is used. be able to.

The head portions 52A and 52B use scale members 54A and 54B, respectively, to measure the X-axis position (X position) and Z-axis position (Z position) of the grating RG2a and RG2b, and the XZ linear encoder and Y. A YZ linear encoder that measures an axial position (Y position) and a Z position is configured. Here, the gratings RG2a and RG2b are formed on the upper surfaces of the scale members 54A and 54B fixed on the surface plate 12 via the support members 56, respectively, and the head portions 52A and 52B are integrated with the mark detection system MDS. It is provided on the head mounting member 51 of the above. As a result, the head portions 52A and 52B measure the position of the surface plate 12 with respect to the mark detection system MDS (the positional relationship between the mark detection system MDS and the surface plate 12). In the following, for convenience, the XZ linear encoder and the YZ linear encoder are referred to as the XZ linear encoders 58X ₁ , 58X ₂ , and the YZ linear _{encoders 58X 1, 58X 2, and YZ linear using the same reference numerals as the XZ heads 58X 1} , 58X ₂ , and the YZ heads 58Y ₁ , 58Y _{2, respectively.} Notated as encoders 58Y ₁ and 58Y ₂ (see FIG. 6).

In the present embodiment, the XZ linear encoder 58X ₁ and the YZ linear encoder 58Y ₁ measure the position information in each of the X-axis, Y-axis, Z-axis, and θx directions with respect to the mark detection system MDS of the surface plate 12. encoder 58 ₁ is constituted (see Fig. 6). Similarly, the 4-axis encoder 58 that measures the position information in each of the X-axis, Y-axis, Z-axis, and θx directions with respect to the mark detection system MDS of the surface plate 12 by the XZ linear encoder 58X ₂ and the YZ linear encoder 58Y _{2. 2} is configured (see FIG. 6). In this case, on the basis of the positional information in the Z axis direction with respect to four axes encoder ₅₈ 1, 58 ₂ at mark detection system of the surface plate 12 to be measured respectively MDS, the position information about the θy direction with respect to the mark detecting system MDS of the surface plate 12 sought (measured), 4 based on the axis encoder ₅₈ 1, 58 ₂ in the position information in the Y-axis directions with respect to the mark detecting system MDS of the surface plate 12 to be measured, respectively, [theta] z direction with respect to the mark detecting system MDS of the surface plate 12 Location information is required (measured).

Thus, relative by four axes encoder 58 ₁ and 4 and the shaft encoder 58 _2, 6 degrees of freedom for the location information of the mark detection system MDS of the surface plate 12, i.e. about 6 degrees of freedom of the mark detection system MDS and a platen 12 A second position measurement system 50 that measures position information is configured. Information on the relative position of the mark detection system MDS and the platen 12 measured by the second position measurement system 50 with respect to the six degrees of freedom direction is constantly supplied to the control device 60, and the control device 60 is at this relative position. Specifically, the detection point of the first position measurement system 30 so that the detection point of the first position measurement system 30 has a desired positional relationship with respect to the detection center of the mark detection system MDS based on the information. However, three vibration isolations are made so that the detection center of the mark detection system MDS and the position in the XY plane match, for example, at the nm level, and the surface of the wafer W on the slider 10 matches the detection position of the mark detection system MDS. The actuator of the device 14 is controlled in real time. At this time, for example, the straight line CL described above coincides with the reference axis LV. If the detection point of the first position measurement system 30 can be controlled so as to have a desired positional relationship with respect to the detection center of the mark detection system MDS, the second position measurement system 50 has 6 degrees of freedom. It is not necessary to be able to measure relative position information in all directions.

FIG. 6 shows a block diagram showing an input / output relationship of the control device 60 that mainly constitutes the control system of the measurement device 100 according to the present embodiment. The control device 60 includes a workstation (or a microprocessor) and the like, and controls each component of the measuring device 100 in an integrated manner. As shown in FIG. 6, the measuring device 100 includes a wafer transfer system 70 arranged in the chamber together with the components shown in FIG. The wafer transfer system 70 includes, for example, a horizontal articulated robot.

Next, in the measuring device 100 according to the present embodiment configured as described above, a series of operations when processing one lot of wafers is based on the flowchart of FIG. 7 corresponding to the processing algorithm of the control device 60. I will explain.

As a premise, the wafer W to be measured by the measuring device 100 is a 300 mm wafer, and a plurality of, for example, I (I = 98 as an example) shot regions are formed on the wafer W due to the exposure before the presheaf layer. Areas (hereinafter also referred to as shots) are formed in a matrix-like arrangement, and a plurality of types of marks, for example, multiple types of marks, for example, are placed on the street line surrounding each shot or the street line inside each shot (in the case of taking multiple chips per shot). It is assumed that a search alignment mark (search mark) for search alignment, a wafer alignment mark (wafer mark) for fine alignment, and the like are provided. The plurality of types of marks are formed together with the compartment area. In this embodiment, two-dimensional marks are used as search marks and wafer marks.

Further, it is assumed that the measuring device 100 can set a plurality of measurement modes in which the mark detection conditions by the mark detection system MDS are different from each other. As a plurality of measurement modes, for example, A mode in which one wafer mark is detected for all shots for all wafers, and multiple wafer marks are detected for all shots for the first predetermined number of wafers in a lot. , The B mode in which the wafer mark to be detected is determined for each shot and the determined wafer mark is detected for the remaining wafers in the lot can be set according to the detection result of the wafer mark. To do.

Further, it is assumed that the operator of the measuring device 100 inputs the information necessary for the alignment measurement with respect to the wafer W in advance via an input device (not shown) and stores it in the memory of the control device 60. Here, the information required for the alignment measurement includes various information such as the thickness information of the wafer W, the flatness information of the wafer holder WH, the shot region on the wafer W, and the design information of the arrangement of the alignment mark. It is assumed that the measurement mode setting information is input in advance by the operator, for example, via an input device (not shown).

The processing algorithm corresponding to the flowchart of FIG. 7 starts when, for example, an operator instructs the start of measurement. At this time, it is assumed that one lot of wafers is housed in the wafer carrier at a predetermined position. Not limited to this, for example, when the measuring device 100 is connected to a substrate processing device (for example, a coater / developer) in-line, the control system of the board processing device permits the start of transfer of one lot of wafers. It may be started when there is a request and the first wafer is delivered to a predetermined delivery position in response to the request. Note that being connected in-line means that different devices are connected to each other while the wafer (board) transport path is connected. In this sense, "in-line" is used. Use the terms "connection" or "inline connection".

First, in step S102, the count value i of the counter indicating the number of the wafer in the lot is initialized to 1 (i ← 1).

In the next step S104, the wafer W is loaded onto the slider 10. The loading of the wafer W is performed by the wafer transfer system 70 and the vertical moving member on the slider 10 under the control of the control device 60. Specifically, the wafer W is transported from the wafer carrier (or the transfer position) above the slider 10 in the loading position by the wafer transfer system 70, and the vertical movement member is driven up by a predetermined amount by the drive device 13. The wafer W is passed to the vertical moving member. Then, after the wafer transfer system 70 is retracted from above the slider 10, the vertical movement member is driven downward by the driving device 13, so that the wafer W is placed on the wafer holder WH on the slider 10. Then, the vacuum pump 11 is turned on, and the wafer W loaded on the slider 10 is vacuum-sucked by the wafer holder WH. When the measuring device 100 is connected to the substrate processing device in-line, the wafers are sequentially carried in from the wafer transfer system on the substrate processing device side and placed at the delivery position.

In the next step S106, the position (Z position) of the wafer W in the Z-axis direction is adjusted. Prior to the adjustment of the Z position, the control device 60 provides relative position information regarding the Z-axis direction, the θy direction, and the θx direction between the mark detection system MDS and the surface plate 12 measured by the second position measurement system 50. Based on this, the internal pressure of the air mounts of the three vibration isolation devices 14 (driving force in the Z-axis direction generated by the vibration isolation devices 14) is controlled, and the upper surface of the surface plate 12 becomes parallel to the XY plane, and Z The position is set to be a predetermined reference position. Wafer W is considered to have a uniform thickness. Therefore, in step S106, the control device 60 sets the wafer W surface within a range in which the focal position of the optical system can be adjusted by the autofocus function of the mark detection system MDS based on the thickness information of the wafer W in the memory. As described above, the driving force in the Z-axis direction generated by the three vibration isolators 14, for example, the internal pressure of the air mount (the amount of compressed air) is adjusted to drive the platen 12 in the Z-axis direction, and the wafer W surface is driven. Adjust the Z position of. When the measurement unit 40 is provided with the focus position detection system, the control device 60 may adjust the Z position on the wafer surface based on the detection result (output) of the focus position detection system. For example, the mark detection system MDS may include a focal position detection system that detects the position of the wafer W surface in the Z-axis direction via an optical element (objective optical element) at the tip. Further, the Z position on the surface of the wafer W based on the detection result of the focal position detection system can be adjusted by moving the surface plate 12 using the vibration isolator 14 and moving the slider 10 together with the surface plate 12. .. A drive system 20 having a configuration in which the slider 10 can be driven not only in the direction in the XY plane but also in the Z-axis direction, the θx direction, and the θy direction is adopted, and the slider 10 is moved by using the drive system 20. Is also good. The Z position adjustment of the wafer surface may include the inclination adjustment of the wafer surface. By using the drive system 20 to adjust the inclination of the wafer surface, an error (a kind of Abbe error) due to the difference ΔZ between the Z position between the arrangement surface of the grating RG1 and the surface of the wafer W may occur. In that case, at least one of the measures described above may be implemented.

In the next step S108, the search alignment of the wafer W is performed. Specifically, for example, at least two search marks located in the peripheral portion substantially symmetrically with respect to the center of the wafer W are detected by using the mark detection system MDS. The control device 60 controls the drive of the slider 10 by the drive system 20, positions each search mark within the detection area (detection field of view) of the mark detection system MDS, and provides measurement information and measurement information by the first position measurement system 30. The detection signal when the measurement information obtained by the second position measurement system 50 is acquired and the search mark formed on the wafer W is detected by using the mark detection system MDS, and the measurement information (and the second) by the first position measurement system 30. The position information of each search mark is obtained based on the measurement information by the position measurement system 50).

More specifically, the control device 60 is the relative position between the detection result of the mark detection system MDS output from the signal processing device 49 (the detection center (index center) of the mark detection system MDS obtained from the detection signal) and each search mark. The position coordinates of the two search marks on the reference coordinate system are obtained based on the relation) and the measured value of the first position measuring system 30 and the measured value of the second position measuring system 50 at the time of detecting each search mark. Here, the reference coordinate system is an orthogonal coordinate system defined by the length measurement axis of the first position measurement system 30.

After that, the residual rotation error of the wafer W is calculated from the position coordinates of the two search marks, and the slider 10 is slightly rotated so that the rotation error becomes almost zero. As a result, the search alignment of the wafer W is completed. Since the wafer W is actually loaded on the slider 10 in a prealigned state, the deviation of the center position of the wafer W is negligibly small, and the residual rotation error is very small.

In the next step S110, it is determined whether or not the set measurement mode is the A mode. Then, if the determination in step S110 is affirmed, that is, when the A mode is set, the process proceeds to step S112.

In step S112, one wafer mark is measured for each of 98 shots, that is, alignment measurement for all wafers (one-point measurement for all shots, in other words, EGA measurement for all shots). Specifically, the control device 60 measures the position coordinates of each search mark at the time of search alignment described above, and the position coordinates of the wafer mark on the wafer W on the reference coordinate system, that is, the position coordinates of the shot. Ask for. However, in this case, unlike the case of search alignment, the measurement information of the second position measurement system 50 is always used when calculating the position coordinates of the shot. The reason is that, as described above, the control device 60 makes the detection point of the first position measurement system 30 within the detection center of the mark detection system MDS and the XY plane based on the measurement information of the second position measurement system 50. The actuators of the three vibration isolation devices 14 are controlled in real time so that the positions match, for example, at the nm level, and the surface of the wafer W on the slider 10 matches the detection position of the mark detection system MDS. However, at the time of detecting the wafer mark, there is no compensation that the detection point of the first position measurement system 30 coincides with the detection center of the mark detection system MDS in the XY plane, for example, at the nm level. This is because it is necessary to calculate the position coordinates of the shot by considering the amount of deviation as an offset. For example, by using the above offset to correct the detection result of the mark detection system MDS or the measurement value of the first position measurement system 30, the position coordinates of the wafer mark on the wafer W calculated on the reference coordinate system are corrected. can do.

Here, in this one-point measurement of all shots, the control device 60 moves the slider 10 (wafer W) via the drive system 20 in at least one of the X-axis direction and the Y-axis direction to mark the wafer mark. It is positioned within the detection area of the mark detection system MDS. That is, the slider 10 is moved with respect to the mark detection system MDS in the XY plane by the step-and-repeat method, and all shots are measured at one point.

When the measurement unit 40 is provided with the focus position detection system, the control device 60 determines the Z position on the wafer surface based on the detection result (output) of the focus position detection system, as described in step S106. May be adjusted.

When the slider 10 is moved in the XY plane during the alignment measurement (measurement of one point for all shots) for all the wafers in step S112, an eccentric load acts on the surface plate 12 with the movement. The control device 60 feeds and forwards the three vibration isolation devices 14 individually so that the influence of the eccentric load is canceled according to the X and Y coordinate positions of the slider included in the measurement information of the first position measurement system 30. It is controlled, and the driving force in the Z-axis direction generated by each vibration isolator 14 is individually controlled. The control device 60 predicts the eccentric load acting on the surface plate 12 based on the information of the known movement path of the slider 10 without using the measurement information of the first position measurement system 30, and the influence of the eccentric load. The three vibration isolation devices 14 may be individually feed-forward controlled so as to cancel each other out. Further, in the present embodiment, information on the unevenness of the wafer holding surface (the surface defined by the upper end surfaces of a large number of pins of the pin chuck) of the wafer holder WH (hereinafter referred to as holder flatness information) is obtained in advance by experiments or the like. Therefore, when moving the slider 10 in alignment measurement (for example, measurement of one point for all shots), the control device 60 includes a wafer mark to be measured on the surface of the wafer W based on the holder flatness information. The Z position of the surface plate 12 is finely adjusted by feedforward controlling the three vibration isolation devices 14 so that the region is quickly located within the depth of focus of the optical system of the mark detection system MDS. It is not necessary to execute either one or both of the feed-forward control for canceling the influence of the eccentric load acting on the surface plate 12 and the feed-forward control based on the holder flatness information.

If the magnification of the mark detection system MDS can be adjusted, the magnification may be set to a low magnification for search alignment and a high magnification for alignment measurement. Further, if the center position deviation of the wafer W loaded on the slider 10 and the residual rotation error are negligibly small, step S108 may be omitted.

In the one-point measurement of all shots in step S112, the measured value of the position coordinates of the sample shot region (sample shot) in the reference coordinate system used in the EGA calculation described later is detected. The sample shot refers to a plurality of (at least three) shots predetermined as those used in the EGA calculation described later among all the shots on the wafer W. In the one-point measurement of all shots, all shots on the wafer W are sample shots. After step S112, the process proceeds to step S124.

On the other hand, when the determination in step S110 is denied, that is, when the B mode is set, the process proceeds to step S114, and the count value i satisfies a predetermined number K (K satisfies 1 <K <I). It is determined whether or not the natural number is smaller than a predetermined number (for example, 4). The count value i is incremented in step S128, which will be described later. Then, if the determination in step S114 is affirmed, the process proceeds to step S120, and all-shot multipoint measurement is performed. Here, the multi-point measurement of all shots means that a plurality of wafer marks are measured for all shots on the wafer W. A plurality of wafer marks to be measured are predetermined. For example, a plurality of wafer marks having an arrangement in which the shape of the shot (shape error from the ideal grid) can be obtained by statistical calculation may be measured. Since the measurement procedure is the same as the case of one-point measurement of all shots in step S112 except that the number of marks to be measured is different, detailed description thereof will be omitted. After step S120, the process proceeds to step S124.

On the other hand, if the determination in step S114 is denied, the process proceeds to step S116, and it is determined whether or not the count value i is smaller than K + 1. Here, the determination in step S116 is affirmed when the count value i is i ≧ K and i <k + 1, so i = K.

If the determination in step S116 is affirmed, the process proceeds to step S118, and the result of detecting the wafer mark on the wafer W of K-1 wafers (for example, 3 wafers in the case of K = 4) measured up to that point is obtained. Based on this, the wafer mark to be measured is determined for each shot. Specifically, for each shot, it is determined whether the detection of one wafer mark is sufficient or whether a plurality of wafer marks should be detected. In the latter case, it is also determined which wafer mark is to be detected. For example, the difference (absolute value) between the measured position and the design position of each of a plurality of wafer marks is obtained for each shot, and whether or not the difference between the maximum value and the minimum value of the difference exceeds a certain threshold value is used for each shot. In addition, it is determined whether a plurality of wafer marks should be detected or whether the detection of one wafer mark is sufficient. In the former case, the wafer mark to be detected is determined so as to include, for example, the wafer mark that maximizes the difference (absolute value) between the measured position and the design position and the wafer mark that minimizes the difference (absolute value). After step S118, the process proceeds to step S122.

On the other hand, if the determination in step S116 is denied, the process proceeds to step S122. Here, the determination in step S116 is denied when the count value i satisfies K + 1 ≦ i, and before that, the count value i = K and the measurement target for each shot in step S118. The wafer mark to be used has been determined.

In step S122, the wafer mark to be measured, which is determined for each shot in step S118, is measured. Since the measurement procedure is the same as the case of one-point measurement of all shots in step S112 except that the number of marks to be measured is different, detailed description thereof will be omitted. After step S122, the process proceeds to step S124.

As can be seen from the explanation so far, in the B mode, all shots are measured at multiple points for the first to K-1th wafers (for example, the third wafer) in the lot. For the wafers from the Kth wafer (for example, the 4th wafer) to the Ith wafer (for example, the 25th wafer), all shots of the first K-1 wafer (for example, 3 wafers) are multipointed. Based on the measurement result, the wafer mark determined for each shot is measured.

In step S124, the EGA calculation is performed using the position information of the wafer mark measured in any of the steps S112, S120, and S122. The EGA calculation is a shot using statistical calculation such as the least squares method based on the data of the difference between the design value and the measured value of the position coordinates of the sample shot after the above-mentioned wafer mark measurement (EGA measurement). It means a statistical operation to obtain the coefficient of the model formula expressing the relationship between the position coordinates of the shot and the correction amount of the position coordinates of the shot.

In the present embodiment, as an example, the following model formula is used to calculate the correction amount from the design value of the position coordinates of the shot.

Here, dx and dy are correction amounts in the X-axis direction and Y-axis direction from the design value of the position coordinates of the shot, and X and Y are the design of the shot in the wafer coordinate system with the center of the wafer W as the origin. The upper position coordinates. That is, the above equation (1) is a polynomial relating to the design position coordinates X and Y of each shot in the wafer coordinate system with the center of the wafer as the origin, and the position coordinates X and Y and the position coordinates of the shot are It is a model formula that expresses the relationship between the correction amount (alignment correction component) dx and dy. In the present embodiment, the rotation between the reference coordinate system and the wafer coordinate system is canceled by the search alignment described above. Therefore, in the following, the reference coordinate system and the wafer coordinate system are not particularly distinguished, and all of them are reference coordinate systems. It is explained as if.

By using the model formula (1), the correction amount of the position coordinates of the shot can be obtained from the position coordinates X and Y of the shot of the wafer W. However, in order to calculate this correction amount, it is necessary to obtain _{the coefficients a 0} , a ₁ , ..., b ₀ , b _{1, ....} After the EGA measurement, based on the data of the difference between the design value and the measured value of the position coordinates of the sample shot, the coefficients a ₀ , a ₁ , of the above equation (1) are used by using a statistical calculation such as the least squares method. ..., b ₀ , b ₁ , ... are obtained.

After determining the coefficients a ₀ , a ₁ , ..., b ₀ , b ₁ , ... In the model formula (1), the model formula (1) after the coefficients are determined is used in the design of each shot (partition area) in the wafer coordinate system. By substituting the position coordinates X and Y to obtain the correction amounts dx and dy of the position coordinates of each shot, a true arrangement of a plurality of shots (partition areas) on the wafer W (if only a linear component is used as a deformation component). (Including non-linear components) can be obtained.

By the way, in the case of the wafer W that has already been exposed, the waveform of the detection signal obtained as the measurement result is not always good for all the wafer marks due to the influence of the process up to that point. When the position of the wafer mark whose measurement result (waveform of the detection signal) is defective is included in the above EGA calculation, the position error of the wafer mark whose measurement result (waveform of the detection signal) is defective has coefficients a ₀ and a. It adversely affects the calculation results of ₁ , ..., b ₀ , b _{1, ....}

Therefore, in the present embodiment, the signal processing device 49 sends only the measurement result of the wafer mark having a good measurement result to the control device 60, and the control device 60 uses the positions of all the wafer marks that received the measurement result. Therefore, the above-mentioned EGA operation is executed. The degree of the polynomial in the above equation (1) is not particularly limited. The control device 60 creates the result of the EGA calculation as an alignment history data file in association with the wafer identification information (for example, wafer number, lot number) together with the information about the mark used in the calculation, and internally or externally. Store in the storage device of.

When the EGA calculation in step S124 is completed, the process proceeds to step S126, and the wafer W is unloaded from the slider 10. This unloading is performed by the wafer transfer system 70 and the vertical moving member on the slider 10 in the reverse procedure of the loading procedure in step S104 under the control of the control device 60.

In the next step S128, after incrementing the counter count value i by 1 (i ← i + 1), the process proceeds to step S130 to determine whether or not the count value i is larger than the total number of wafers I in the lot. If the determination in step S130 is denied, it is determined that the processing for all the wafers in the lot has not been completed, and the process returns to step S104 until the determination in step S130 is affirmed. The processing (including determination) from S104 to step S130 is repeated.

Then, when the determination in step S130 is affirmed, it is determined that the processing has been completed for all the wafers in the lot, and the series of processing of this routine is completed.

As described in detail above, according to the measuring device 100 according to the present embodiment, the control device 60 controls the movement of the slider 10 by the drive system 20, and the first position measuring system 30 and the second position measuring system. Using 50, the position information of the slider 10 with respect to the surface plate 12 and the relative position information between the mark detection system MDS and the surface plate 12 are acquired, and a plurality of pieces formed on the wafer W using the mark detection system MDS. I'm looking for the position information of the mark. Therefore, according to the measuring device 100, the position information of the plurality of marks formed on the wafer W can be obtained with high accuracy.

Further, according to the measuring device 100 according to the present embodiment, the control device 60 constantly acquires the measurement information (the relative position information between the platen 12 and the mark detection system MDS) by the second position measuring system 50, and marks the mark. The positional relationship between the detection center of the detection system MDS and the measurement point of the first position measurement system that detects the position information of the slider 10 in the six degrees of freedom direction with respect to the platen 12 is maintained at the desired relationship at the nm level. The position of the platen 12 in the six degrees of freedom direction is controlled in real time via three vibration isolation devices 14 (actuators). Further, the control device 60 controls the drive of the slider 10 by the drive system 20, and the measurement information by the first position measurement system 30 (position information of the slider 10 with respect to the platen 12) and the measurement information by the second position measurement system 50. (Relative position information between the platen 12 and the mark detection system MDS) is acquired, and the detection signal when the mark formed on the wafer W is detected using the mark detection system MDS and the mark detection system MDS are used. The measurement information by the first position measurement system 30 obtained when the mark formed on the wafer W is detected, and the second position measurement system obtained when the mark formed on the wafer W is detected by using the mark detection system MDS. Based on the measurement information by 50, the position information of a plurality of wafer marks is obtained. Therefore, according to the measuring device 100, the position information of the plurality of marks formed on the wafer W can be obtained with high accuracy.

For example, the position of the wafer W (wafer stage WST) at the time of exposure, which will be described later, is controlled based on the measured mark position information without performing the EGA calculation using the measured mark position information. In some cases, for example, the measurement information by the second position measurement system 50 may not be used for calculating the mark position information. However, in this case, the measurement information obtained by the second position measurement system 50 obtained when the mark formed on the wafer W is detected by using the mark detection system MDS is offset and used, for example, the wafer W (wafer stage). Information for moving the wafer W, such as the positioning target value of WST), may be corrected. Alternatively, the movement of the reticle R (reticle stage RST), which will be described later, may be controlled in consideration of the above offset.

Further, according to the measuring device 100 according to the present embodiment, at the time of alignment measurement, the position information of at least one wafer mark is measured for each of I (for example, 98) shots on the wafer W, and this position information. _{The coefficients a 0} , a ₁ , ..., b ₀ , b ₁ , ... Of the above equation (1) can be obtained by statistical calculation such as the least squares method. Therefore, it is possible to accurately obtain not only the linear component but also the non-linear component of the deformation component of the wafer grid. Here, the wafer grid means a grid formed by connecting the centers of shots on the wafer W arranged according to a shot map (data relating to the arrangement of shots formed on the wafer W).

Further, according to the measuring device 100 according to the present embodiment, the first position measuring system 30 for measuring the position information in the six degrees of freedom direction of the slider 10 on which the wafer W is placed and held is at least the wafer mark on the wafer W. Is detected by the mark detection system MDS, so that the measurement beam can be continuously irradiated to the grating RG1 from the head portion 32 within the range in which the slider 10 moves. Therefore, the first position measurement system 30 can continuously measure the position information in the entire range in the XY plane in which the slider 10 moves for mark detection. Therefore, for example, in the manufacturing stage of the measuring device 100 (including the start-up stage of the device in the semiconductor manufacturing factory), the Cartesian coordinate system (reference coordinate system) defined by the length measuring axis of the first position measuring system 30. By setting the origin, the mark (search mark, wafer mark) on the wafer W held on the slider 10 is obtained from the absolute position of the slider 10, the position information of the slider 10, and the detection result of the mark detection system MDS. It is possible to manage the absolute position of other marks (including, for example, a superposition measurement mark (registration mark)) on the reference coordinate system. In addition, in this specification, an "absolute position" means a coordinate position in a reference coordinate system.

The correction amount of the position coordinates of the shot of the wafer W obtained by the measuring device 100 (coefficients a ₀ , a ₁ , ..., b ₀ , b ₁ , ...) of the above equation (1) is, for example, the wafer W obtained by the exposure apparatus. It is considered that it is used for aligning the wafer with respect to the exposure position at the time of exposure. However, in order to expose the wafer W whose position coordinate correction amount has been measured by the measuring device 100 by the exposure device, it is necessary to unload the wafer W from the slider 10 and then load the wafer W onto the wafer stage of the exposure device. There is. Even if the same type of wafer holder is used for the wafer holder WH on the slider 10 and the wafer holder on the wafer stage of the exposure apparatus, the holding state of the wafer W differs depending on the individual difference of the wafer holder. Therefore, even if the measuring device 100 obtains the correction amount of the position coordinates of the shot of the wafer W (coefficients a ₀ , a ₁ , ..., b ₀ , b ₁ , ... In the above equation (1)), the correction amount is obtained. All of the coefficients a ₀ , a ₁ , ..., b ₀ , b ₁ , ... cannot be used as they are. However, it is the low-order component (linear component) of the first-order or lower order of the correction amount of the position coordinates of the shot that is affected by the different holding state of the wafer W for each wafer holder, and the second-order or higher-order component is affected. It is considered to be almost unaffected. The reason is that the second-order and higher-order components are considered to be components mainly caused by the deformation of the wafer W due to the process, and are considered to be components irrelevant to the holding state of the wafer by the wafer holder. This is because there is no problem.

Based on such idea, the measuring apparatus 100, the coefficient of the high-order component obtained for the wafer W over time _{a 3, a 4, ......,} a 9, ......, and _{b 3, b} 4, ......, b ₉ , ... Can be used as they are as the coefficient of the higher-order component of the correction amount of the position coordinates of the wafer W in the exposure apparatus. Therefore, on the wafer stage of the exposure apparatus, it is sufficient to perform simple EGA measurement (for example, measurement of about 3 to 16 wafer marks) for obtaining the linear component of the correction amount of the position coordinates of the wafer W. Since the measuring device 100 is a device different from the exposure device, it is possible to obtain more mark position information on the substrate without causing a decrease in throughput in the exposure processing of the substrate.

Further, if the measuring device 100 performs the alignment measurement on another wafer in parallel with the wafer processing by the exposure device including the above-mentioned simple EGA measurement and exposure by the exposure device, the throughput of the wafer processing can be almost reduced. Efficient processing that does not decrease is possible.

In the above embodiment, for simplification of the description, either A mode or B mode is set as the measurement mode, but the measurement mode is not limited to this, and all shots on all wafers in the lot are not limited to this. For C mode, which detects two or more first number of wafer marks, and for all wafers in the lot, some shots, for example, two or more pre-determined shots located at the periphery of the wafer. A mode (referred to as D mode) in which two wafer marks are detected and one wafer mark is detected for each of the remaining shots may be provided. Further, an E mode for selecting one of A mode, C mode, and D mode is provided for the remaining wafers in the lot according to the detection result of the wafer mark for the first predetermined number of wafers in the lot. Is also good.

Further, as a measurement mode of the measuring device 100, one or more wafer marks of some shots, for example, 90% or 80% of the shots, may be measured for all the wafers in the lot, or the central portion of the wafer may be measured. For shots located at, one or more wafer marks of one-spaced shots may be measured.

In the above embodiment, the case where the grating RG1, RG2a, and RG2b each have the X-axis direction and the Y-axis direction as the periodic directions has been described, but the present invention is not limited to this, and the first position measurement system 30 and the second position measurement are not limited to this. The lattice portion (two-dimensional grating) included in each of the systems 50 may have two directions intersecting each other in the XY plane as periodic directions.

Further, it goes without saying that the configuration of the head portion 32 of the first position measurement system 30 and the arrangement of the detection points described in the above embodiment are only examples. For example, the detection point of the mark detection system MDS and the detection center of the head portion 32 do not have to coincide with each other in at least one of the X-axis direction and the Y-axis direction. Further, the arrangement of the head portion of the first measurement system 30 and the grating RG1 (grid portion) may be reversed. That is, the slider 10 may be provided with a head portion, and the surface plate 12 may be provided with a grid portion. Further, the first position measurement system 30 does not necessarily have to include the encoder system 33 and the laser interferometer system 35, and the first position measurement system 30 may be configured only by the encoder system. The first is by an encoder system that irradiates the grating RG1 of the slider 10 from the head portion, receives the return beam (diffraction beam) from the grating, and measures the position information of the slider 10 in the six degrees of freedom direction with respect to the surface plate 12. A position measurement system may be configured. In this case, the configuration of the head of the head portion is not particularly limited. For example, a pair of XZ heads that irradiate two points on the grating RG1 that are the same distance apart in the X-axis direction with a detection beam, and two points that are the same distance apart in the Y-axis direction from the predetermined point are detected. A pair of YZ heads that irradiate the beam may be provided, or a pair of three-dimensional heads that irradiate the detection beam at two points separated in the X-axis direction of the grating RG1 and the above two points are , An XZ head or a YZ head that irradiates a detection beam at different positions in the Y-axis direction may be provided. The first position measurement system 30 does not necessarily have to be able to measure the position information of the slider 10 in the six degrees of freedom direction with respect to the surface plate 12, and may only be able to measure the position information in the X, Y, and θz directions, for example. Further, a first position measuring system for measuring the position information of the slider 10 with respect to the surface plate 12 may be arranged between the surface plate 12 and the slider 10.

Similarly, the configuration of the second position measurement system 50 described in the above embodiment is only an example. For example, the head portions 52A and 52B may be fixed to the surface plate 12 side, and the scales 54A and 54B may be provided integrally with the mark detection system MDS. Further, the case where the second measurement system 50 includes a pair of head portions 52A and 52B has been illustrated, but the present invention is not limited to this, and the second measurement system 50 may include only one head portion. It may have three or more. In any case, it is desirable that the second position measurement system 50 can measure the positional relationship between the surface plate 12 and the mark detection system MDS in the six degrees of freedom direction. However, the second measurement system 50 does not necessarily have to be able to measure the positional relationship in all six degrees of freedom direction.

In the above embodiment, the slider 10 is floated and supported on the surface plate 12 by a plurality of air bearings 18 to drive the slider 10 in the X-axis direction, and the slider 10 is driven by the first drive device 20A. The case where the drive system 20 for driving the slider 10 in a non-contact state with respect to the surface plate 12 is configured including the second drive device 20B for driving in the Y-axis direction integrally with the surface plate 12 has been described. However, the present invention is not limited to this, and a drive system having a configuration in which the slider 10 is driven in the direction of 6 degrees of freedom on the surface plate 12 may be adopted as the drive system 20. Such a drive system may be configured by a magnetic levitation type flat motor as an example. In such a case, the air bearing 18 becomes unnecessary. The measuring device 100 may include a drive system for driving the surface plate 12 in addition to the vibration isolating device 14.

<< Second Embodiment >>
Next, a second embodiment of the lithography system including the above-mentioned measuring device 100 will be described with reference to FIGS. 8 to 10.

As shown in FIG. 8, the lithography system 1000 according to the second embodiment includes an exposure device 200, a measuring device 100, and a substrate processing device 300 that are connected in-line to each other. Here, since a coater / developer (C / D) is used as the substrate processing apparatus 300, it is also referred to as C / D 300 as appropriate below. The lithography system 1000 is installed in a clean room.

In a normal lithography system, for example, as disclosed in US Pat. No. 6,698,944, for connecting both in-line between an exposure apparatus and a substrate processing apparatus (C / D). An in-line interface section having a wafer transfer system inside the chamber is arranged. On the other hand, as can be seen from FIG. 8, in the lithography system 1000 according to the second embodiment, the measuring device 100 is arranged between the exposure device 200 and the C / D 300 instead of the inline interface unit. There is.

The exposure apparatus 200, the C / D 300, and the measuring apparatus 100 included in the lithography system 1000 all have chambers, and the chambers are arranged adjacent to each other. The exposure control device 220 included in the exposure device 200, the coating development control device 320 included in the C / D 300, and the control device 60 included in the measuring device 100 are connected to each other via a local area network (LAN) 500. Communicate between the three parties. A storage device 400 is also connected to the LAN 500.

The exposure apparatus 200 is, for example, a step-and-scan type projection exposure apparatus (scanner). In FIG. 9, a part of the components in the chamber of the exposure apparatus 200 is omitted.

As shown in FIG. 9, the exposure apparatus 200 projects an image of the illumination system IOP, the reticle stage RST holding the reticle R, and the pattern formed on the reticle R onto the wafer W coated with the sensitive agent (resist). It includes a projection unit PU, a wafer stage WST that holds the wafer W and moves in the XY plane, and a control system for these. The exposure apparatus 200 includes a projection optical system PL having an optical axis AX in the Z-axis direction parallel to the optical axis AX1 of the mark detection system MDS described above.

The illumination system IOP includes a light source and an illumination optical system connected to the light source via a light transmission optical system, and is set (restricted) by a reticle blind (masking system) in the X-axis direction (in FIG. 9). The slit-shaped illumination region IAR extending in the direction perpendicular to the paper surface is illuminated by the illumination light (exposure light) IL with substantially uniform illuminance. The configuration of the lighting system IOP is disclosed, for example, in US Patent Application Publication No. 2003/0025890. Here, as the illumination light IL, ArF excimer laser light (wavelength 193 nm) is used as an example.

The reticle stage RST is arranged below the lighting system IOP in FIG. The reticle stage RST can be micro-driven in a horizontal plane (XY plane) on a reticle stage platen (not shown in FIG. 9) by a reticle stage drive system 211 (not shown in FIG. 9, see FIG. 10) including, for example, a linear motor. At the same time, it can be driven in a predetermined stroke range in the scanning direction (the Y-axis direction which is the left-right direction in the paper surface in FIG. 9).

On the reticle stage RST, a reticle R on which a pattern region and a plurality of marks whose positional relationship with the pattern region is known is formed on a surface (pattern surface) on the −Z side is placed. The position information (including rotation information in the θz direction) of the reticle stage RST in the XY plane is formed on the end face of the moving mirror 212 (or the end face of the reticle stage RST) by the reticle laser interferometer (hereinafter referred to as “reticle interferometer”) 214. It is always detected with a resolution of, for example, about 0.25 nm through the reflected surface. The measurement information of the reticle interferometer 214 is supplied to the exposure control device 220 (see FIG. 10). The position information of the reticle stage RST in the XY plane may be measured by an encoder instead of the reticle laser interferometer 214.

The projection unit PU is arranged below the reticle stage RST in FIG. The projection unit PU includes a lens barrel 240 and a projection optical system PL held in the lens barrel 240. The projection optical system PL is, for example, bilateral telecentric and has a predetermined projection magnification (for example, 1/4 times, 1/5 times, 1/8 times, etc.). The reticle R is arranged so that the first surface (object surface) of the projection optical system PL and the pattern surface substantially coincide with each other, and the wafer W coated with the resist (sensitizer) on the surface is the second surface of the projection optical system PL. It is arranged on the surface (image surface) side. Therefore, when the illumination region IAR on the reticle R is illuminated by the illumination light IL from the illumination system IOP, the illumination light IL passing through the reticle R reduces the circuit pattern of the reticle R in the illumination region IAR. A reduced image of a part of the circuit pattern) is formed in a region (hereinafter, also referred to as an exposure region) IA on the wafer W conjugated to the illumination region IAR via the projection optical system PL. Then, by synchronously driving the reticle stage RST and the wafer stage WST, the reticle R is moved relative to the illumination region IAR (illumination light IL) in the scanning direction (Y-axis direction), and the exposure region IA (illumination light IL) is moved. By moving the wafer W relative to the scanning direction (Y-axis direction), scanning exposure of one shot region (partition region) on the wafer W is performed, and the pattern of the reticle R is transferred to the shot region. To.

As the projection optical system PL, for example, a refraction system composed of only a plurality of refracting optical elements (lens elements) arranged along the optical axis AX parallel to the Z-axis direction, for example, about 10 to 20 elements is used. There is. Of the plurality of lens elements constituting the projection optical system PL, the plurality of lens elements on the object surface side (reticle R side) are driven in the Z-axis direction (projection optics) by a driving element (not shown) such as a piezo element. It is a movable lens that can be shifted in the optical axis direction of the system PL and driven in the tilt direction (that is, the θx direction and the θy direction) with respect to the XY plane. Then, the imaging characteristic correction controller 248 (not shown in FIG. 9, see FIG. 10) independently adjusts the applied voltage to each driving element based on the instruction from the exposure control device 220, so that each movable lens can be moved. It is individually driven and various imaging characteristics (magnification, distortion, astigmatism, coma, curvature of field, etc.) of the projection optical system PL are adjusted. Instead of or in addition to the movement of the movable lens, an airtight chamber is provided between specific adjacent lens elements inside the lens barrel 240, and the pressure of the gas in the airtight chamber is measured by the imaging characteristic correction controller 248. The configuration may be controlled, or the configuration in which the imaging characteristic correction controller 248 can shift the center wavelength of the illumination light IL may be adopted. The imaging characteristics of the projection optical system PL can also be adjusted by these configurations.

The wafer stage WST has a predetermined stroke in the X-axis direction and the Y-axis direction on the wafer stage platen 222 by a stage drive system 224 (shown by a block in FIG. 9 for convenience) including a flat motor or a linear motor. In addition to being driven by, it is minutely driven in the Z-axis direction, the θx direction, the θy direction, and the θz direction. The wafer W is held on the wafer stage WST via a wafer holder (not shown) by vacuum suction or the like. In the second embodiment, the wafer holder can suck and hold a 300 mm wafer. Instead of the wafer stage WST, a first stage that moves in the X-axis direction, the Y-axis direction, and the θz direction, and a second stage that slightly moves in the Z-axis direction, the θx direction, and the θy direction on the first stage are used. It is also possible to use a stage device provided. In addition, either one or both of the wafer stage WST and the wafer holder of the wafer stage WST may be referred to as a "second substrate holding member".

Position information of the wafer stage WST in the XY plane (including rotation information (yaw amount (rotation amount θz in the θz direction), pitching amount (rotation amount θx in the θx direction), rolling amount (rotation amount θy in the θy direction))) Is constantly detected by a laser interferometer system (hereinafter abbreviated as an interferometer system) 218 through a moving mirror 216 (or a reflecting surface formed on the end face of the wafer stage WST) with a resolution of, for example, about 0.25 nm. Will be done. The position information of the wafer stage WST in the XY plane may be measured by an encoder system instead of the interferometer system 218.

The measurement information of the interferometer system 218 is supplied to the exposure control device 220 (see FIG. 10). The exposure control device 220 controls the position (including rotation in the θz direction) of the wafer stage WST in the XY plane via the stage drive system 224 based on the measurement information of the interferometer system 218.

Further, although not shown in FIG. 9, the position and the amount of inclination of the surface of the wafer W in the Z-axis direction are many of the oblique incident methods disclosed in, for example, US Pat. No. 5,448,332. It is measured by a focus sensor AFS (see FIG. 10) including a point focus position detection system. The measurement information of the focus sensor AFS is also supplied to the exposure control device 220 (see FIG. 10).

Further, on the wafer stage WST, a reference plate FP whose surface is the same height as the surface of the wafer W is fixed. On the surface of the reference plate FP, a first reference mark used for baseline measurement of the alignment detection system AS and a pair of second reference marks detected by the reticle alignment detection system described later are formed.

On the side surface of the lens barrel 240 of the projection unit PU, an alignment detection system AS for detecting the alignment mark or the first reference mark formed on the wafer W is provided. As an alignment detection system AS, for example, it is a kind of imaging type alignment sensor of the image processing method that measures the mark position by illuminating the mark with broadband (broadband) light such as a halogen lamp and processing the image of this mark. A certain FIA (Field Image Alignment) system is used. In addition, instead of the alignment detection system AS of the image processing method, or together with the alignment detection system AS, a diffracted light interference type alignment system may be used.

Further, in the exposure apparatus 200, a pair of reticle alignment detection systems 213 (FIG. 9) capable of simultaneously detecting a pair of reticle marks at the same Y position on the reticle R mounted on the reticle stage RST above the reticle stage RST. (Not shown, see FIG. 10) are provided at predetermined distances in the X-axis direction. The mark detection result by the reticle alignment detection system 213 is supplied to the exposure control device 220.

In FIG. 10, the input / output relationship of the exposure control device 220 is shown in a block diagram. As shown in FIG. 10, the exposure device 200 includes, in addition to the above-mentioned components, a wafer transfer system 270 and the like connected to the exposure control device 220 to transfer wafers. The exposure control device 220 includes a microcomputer, a workstation, and the like, and controls the entire device including the above-mentioned components in an integrated manner. The wafer transfer system 270 includes, for example, a horizontal articulated robot.

Returning to FIG. 8, although not shown, the C / D 300 has, for example, a coating unit for applying a sensitive agent (resist) to the wafer, a developing unit capable of developing the wafer, and prebaking (PB) and developing. It includes a baking unit for performing post-exposure bake (PEB) and a wafer transfer system (hereinafter, referred to as a C / D intra-convey system for convenience). The C / D 300 further includes a temperature control unit 330 capable of controlling the temperature of the wafer. The temperature control unit 330 is usually a cooling unit, and includes, for example, a flat plate (temperature control device) called a cool plate. The cool plate is cooled by, for example, circulation of cooling water. In addition, electronic cooling by the Peltier effect may be used.

The storage device 400 includes a management device connected to the LAN 500 and a storage device connected to the management device via a communication path such as SCSI (SCSI).

In the lithography system 1000 according to the second embodiment, the measuring device 100, the exposure device 200, and the C / D 300 all include a barcode reader (not shown), and the wafer transfer system 70 (see FIG. 6). During wafer transfer by the wafer transfer system 270 (see FIG. 10) and the in-C / D transfer system (not shown), the barcode reader can read the identification information of each wafer, such as the wafer number and lot number. It is done as appropriate. Hereinafter, for the sake of simplification of the description, the description regarding the reading of the identification information of each wafer using the barcode reader will be omitted.

In the lithography system 1000, a large number of wafers are continuously processed by each of the exposure device 200, the C / D 300, and the measuring device 100 (hereinafter, appropriately referred to as three devices 100, 200, 300). In the lithography system 1000, the entire processing is performed so that the throughput of the entire system is maximized, that is, the processing time of the device that takes the longest processing, for example, completely overlaps the processing time of the other device. The sequence is defined.

Hereinafter, the operation flow when a large number of wafers are continuously processed by the lithography system 1000 will be described.

First, the C / D within the transport system (e.g., a scalar robot), (a W ₁₎ wafer from arranged wafer carrier into the chamber of the first sheet of C / D300 is taken out, it is carried into the coating unit .. As a result, the coating portion starts coating the resist. When the application of the resist is completed, the transfer system in the C / D _{takes out the wafer W 1} from the coating portion and carries it into the baking portion. Accordingly, heat treatment of the wafer W ₁ (PB) is started by the baking unit. Then, when the PB of the wafer is completed, the wafer W ₁ is taken out from the bake portion and carried into the temperature control portion 330 by the transfer system in the C / D. Thus, the wafer W ₁ cooling is started by the temperature control unit 330 inside the cool plate. This cooling is performed with a temperature that does not affect the exposure device 200, generally, a target temperature of the air conditioning system of the exposure device 200 defined in the range of, for example, 20 to 25 ° C. as a target temperature. Normally, the temperature of the wafer is within the range of ± 0.3 [° C.] with respect to the target temperature at the time of being carried into the temperature control unit 330, but the target temperature of ± 10 [mK] is set by the temperature control unit 330. The temperature is adjusted to the range.

Then, when cooling (temperature control) is completed in the temperature control section 330, the wafer W ₁ is transferred to the first substrate transfer section provided between the C / D 300 and the measuring device 100 by the transport system in the C / D. Placed on top.

In the C / D 300, resist coating, PB, cooling, and the above-mentioned wafer transfer operation associated with the series of processing are sequentially repeated on a series of wafers similar to the above, and the wafers are sequentially placed on the first substrate transfer section. It is placed in. Actually, by providing two or more coating portions and two or more transfer systems in the C / D in the chamber of the C / D 300, parallel processing can be performed on a plurality of wafers, and the time required for the pre-exposure processing. Can be shortened.

_{In the measuring device 100, the wafer W 1} before exposure, which is sequentially placed on the first substrate transfer portion by the transfer system in the C / D, is first moved by the joint work of the wafer transfer system 70 and the vertical moving member on the slider 10. Load onto the slider 10 according to the procedure described in the first embodiment. After loading, the measuring device 100 performs the alignment measurement of the wafer in the set measurement mode, and the control device 60 corrects the position coordinates of the shot of the wafer W (coefficients a ₀ , a of the above equation (1)). ₁ , ..., b ₀ , b ₁ , ...) are required.

The control device 60 uses the correction amount of the obtained position coordinates (coefficients a ₀ , a ₁ , ..., b ₀ , b ₁ , ...) of the above equation (1), and the position information of the mark for calculating the correction amount. Alignment history data by associating history information such as wafer mark information, measurement mode information, and all wafer mark information with good detection signals with wafer W ₁ identification information (wafer number, lot number). (File) is created and stored in the storage device 400.

Thereafter, the wafer W ₁ which alignment measurement is completed, the wafer transport system 70, the chamber inside of the exposure apparatus 200, placing the load side substrate platform of the second substrate transfer unit provided in the vicinity of the measuring device 100 Place. Here, the second substrate delivery portion is provided with a load-side substrate mounting portion and an unload-side substrate mounting portion.

Thereafter, the measuring apparatus 100, the second and subsequent wafers, the same procedure as the wafer W _1, alignment measurement, creating alignment history data (file), so that the conveyance of the wafer is repeated.

Wafer W ₁ mounted on the load side substrate platform described above, the wafer transport system 270, is transported to a predetermined waiting position inside the exposure device 200. However, the first wafer W ₁ is immediately loaded onto the wafer stage WST by the exposure control device 220 without waiting at the standby position. The loading of the wafer is performed by the exposure control device 220 using the vertically moving member (not shown) on the wafer stage WST and the wafer transfer system 270 in the same manner as performed by the measuring device 100 described above. After loading, the wafer on the wafer stage WST is subjected to the same search alignment as described above using the alignment detection system AS, and an EGA-type wafer alignment in which shots of, for example, about 3 to 16 are used as alignment shots. In the case of this EGA type wafer lining, the exposure control device 220 of the exposure device 200 uses the alignment history data file stored in the storage device 400 as identification information (for example, target wafer) of the wafer (target wafer) to be subjected to wafer alignment and exposure. The wafer number, lot number) is used as a key to search, and the alignment history data of the target wafer is acquired. Then, after the predetermined preparatory work, the exposure control device 220 performs the following wafer alignment according to the measurement mode information included in the acquired alignment history data.

First, a case where the information of the mode A is included will be described. In this case, the number of wafer marks whose position information has been measured by the measuring device 100 (where the mark position information was used to calculate the correction amount) included in the alignment history data corresponds to the number of alignment shots. A wafer mark is selected to be detected, the wafer mark to be detected is detected using the alignment detection system AS, and the detection result and the position of the wafer stage WST at the time of detection (measurement information by the interferometer system 218) Based on the above, the position information of each wafer mark to be detected is obtained, and the EGA calculation is performed using the position information to obtain each coefficient of the following equation (2).

Then, the exposure control device 220 uses the coefficients (c ₀ , c ₁ , c ₂ , d ₀ , d ₁ , d _{2 ) obtained here as the coefficients (a 0} , a ₁ , a ₂ ) included in the alignment history data. , B ₀ , b ₁ , b ₂ ), and the design position coordinates X, Y of each shot in the wafer coordinate system with the center of the wafer represented by the following equation (3) including the coefficient after replacement as the origin. The correction amount (alignment correction component) dx and dy of the position coordinates of each shot is obtained by using the polynomial with respect to, and the exposure position (reticle) at the time of exposure of each shot for correcting the wafer grid based on this correction amount. A target position (hereinafter, referred to as a positioning target position for convenience) for alignment with respect to the projected position of the pattern is determined. In the present embodiment, the exposure is performed by the scanning exposure method instead of the static exposure method, but for convenience, it is referred to as a positioning target position.

Even in the exposure apparatus 200, the search alignment cancels the rotation between the reference coordinate system (stage coordinate system) that defines the movement of the wafer stage WST and the wafer coordinate system, so that the reference coordinate system and the wafer coordinate system are particularly distinguished. do not have to.

Next, the case where the B mode is set will be described. In this case, the exposure control device 220 determines the positioning target position of each shot for correcting the wafer grid according to the same procedure as in the case of the A mode described above. However, in this case, in the alignment history data, of the plurality of wafer marks for some shots and one wafer mark for each of the remaining shots, the wafer mark having a good detection signal is the correction amount. It is included as a wafer mark in which the position information of the mark is used in the calculation.

Therefore, in addition to determining the positioning target position of each shot described above, the exposure control device 220 selects the number of wafer marks required to obtain the shot shape from the plurality of wafer marks for some of the shots described above. Then, using the position information (actual measurement value) of those wafer marks, for example, a statistical calculation that applies the least squares method to the model formula of [Equation 7] disclosed in US Pat. No. 6,876,946. (Also called multi-point EGA calculation in shot) is performed to obtain the shot shape. Specifically, among the 10 parameters in the model formula of [Equation 7] disclosed in the above-mentioned US Pat. No. 6,876,946, the chip rotation (θ) and the orthogonality error of the chip ( w), and the chip scaling (rx) in the x direction and the chip scaling (ry) in the y direction are obtained. Since the multi-point EGA calculation in the shot is disclosed in detail in the above-mentioned US patent, detailed description thereof will be omitted.

_{Then, the exposure control device 220 exposes each shot on the wafer W 1} by a step-and-scan method while controlling the position of the wafer stage WST according to the positioning target position. Here, when the shot shape is also obtained by multi-point EGA measurement in the shot, the projected image of the reticle R pattern by the projection optical system PL is deformed according to the obtained shot shape during scanning exposure. Reticle stage RST and wafer stage WST relative scanning angle, scanning speed ratio, relative position of reticle stage RST and wafer stage WST with respect to at least one projection optical system, imaging characteristics (aberration) of projection optical system PL, and illumination light. (Exposure light) At least one of the wavelengths of IL is adjusted. Here, the adjustment of the imaging characteristic (aberration) of the projection optical system PL and the adjustment of the center wavelength of the illumination light IL are performed by the exposure control device 220 via the imaging characteristic correction controller 248.

In parallel with the EGA wafer alignment and exposure of the wafer (in this case, wafer W ₁ ) on the wafer stage WST, the measuring device 100 attaches the second wafer (referred to as wafer W ₂ ) to the second wafer. On the other hand, wafer alignment measurement in the set mode, creation of alignment history data, and the like are executed by the above-mentioned procedure.

Then, before the exposure of the wafer on the wafer stage WST (in this case, the wafer W ₁ ) is completed, the measurement process of the measuring device 100 is completed, and the second wafer W ₂ is loaded on the load side by the wafer transfer system 70. It is mounted on the substrate mounting portion, is transported to a predetermined standby position inside the exposure apparatus 200 by the wafer transfer system 270, and stands by at the standby position.

When the exposure of the wafer W ₁ is completed, the wafer W ₁ and the wafer W ₂ are exchanged on the wafer stage, and the exchanged wafer W _{2 is} subjected to the same wafer alignment and exposure as described above. If the transfer of the wafer W _{2 to} the standby position is not completed by the time the exposure of the wafer on the wafer stage (in this case, the wafer W ₁ ) is completed, the wafer stage stands by while holding the exposed wafer. It will wait near the position.

In parallel with the wafer alignment with respect to the exchanged wafer W _{2, the exposed wafer W 1} is transported to the unload-side substrate mounting portion of the second substrate transfer portion by the wafer transfer system 270.

After that, as described above, the wafer transfer system 70 moves the exposed wafer from the unload side substrate mounting portion to the first substrate transfer portion in parallel with the wafer alignment measurement being performed by the measuring device 100. The operation of transporting and mounting the wafer and the operation of taking out the unexposed wafer after the measurement from the top of the slider 10 and transporting the wafer to the load-side substrate mounting portion are repeated in a predetermined order.

As described above, the exposed wafer transported and placed on the first substrate transfer section by the wafer transfer system 70 is carried into the bake section by the transfer system in the C / D, and the baking apparatus in the bake section. PEB is performed by. A plurality of wafers can be accommodated in the bake portion at the same time.

On the other hand, the wafer for which PEB has been completed is taken out from the baking section by the transport system in the C / D, carried into the developing section, and the development is started by the developing device in the developing section.

Then, when the development of the wafer is completed, the wafer is taken out from the developing unit by the transfer system in the C / D and carried into a predetermined storage stage in the wafer carrier. Later, within the C / D300, with respect to the exposed second and subsequent wafers, the same procedure as the wafer W _1, PEB, development, and so that the conveyance of the wafer is repeated.

As described above, according to the lithography system 1000 according to the second embodiment, the wafer alignment measurement can be performed by the measuring device 100 in parallel with the operation of the exposure device 200, and all shots are sampled. All shot EGAs to be shots can be performed in parallel with the wafer alignment and exposure operations of the exposure apparatus 200. Further, since the coefficients of the higher-order components in the model formula obtained by the all-shot EGA can be adopted as they are in the exposure apparatus 200, the exposure apparatus 200 performs the alignment measurement with several shots as the alignment shots and described above. By only obtaining the coefficient of the low-order component of the model formula, and using the coefficient of this low-order component and the coefficient of the high-order component acquired by the measuring device 100, the exposure device 200 uses the low-order component of the model formula (1). It is possible to calculate the positioning target position at the time of exposure of each shot with the same accuracy as when the coefficients of the next and higher order components are obtained. Therefore, it is possible to improve the overlay accuracy of the image of the reticle pattern at the time of exposure and the pattern formed in each shot region on the wafer without reducing the throughput of the exposure apparatus 200.

In the lithography system 1000 according to the second embodiment, for example, when the wafer processing throughput of the entire lithography system 1000 is not lowered more than necessary, the developed wafer is the same as the wafer before exposure after PB described above. The displacement of the overlay deviation measurement mark (for example, a box-in-box mark) formed on the wafer may be measured by loading the wafer 10 on the slider 10 of the measuring device 100 again according to the above procedure. That is, since the measuring device 100 can measure the absolute value of the mark on the wafer (on the reference coordinate system by the first position measuring system 30), it is not only the wafer alignment measurement but also the superposition deviation which is a kind of relative position measurement. It is also suitable as a measuring device for measuring the misalignment of the measurement mark.

In the lithography system 1000 according to the second embodiment, the exposure apparatus 200 obtains the coefficients of the low-order components of the first-order or lower of the above model formula, and the coefficients of the low-order components and the coefficients of the low-order components are acquired by the measuring device 100. The case where the coefficient of the second-order or higher-order component of the above model formula is used has been described. However, the present invention is not limited to this, for example, the coefficient of the second or lower component of the above model formula is obtained from the detection result of the alignment mark in the exposure device 200, and the coefficient of the second or lower component and the coefficient of the second or lower component are acquired by the measuring device 100. You may also use the coefficient of the third-order or higher-order component of the above model formula. Alternatively, for example, the coefficient of the third-order or lower component of the above model formula is obtained from the detection result of the alignment mark in the exposure apparatus 200, and the coefficient of the third-order or lower component and the coefficient of the third-order or lower component acquired by the measuring device 100 are obtained. Coefficients of higher-order components of the fourth or higher order may be used. That is, the coefficients of the components of the (N-1) order (N is an integer of 2 or more) or less in the above model formula are obtained from the detection result of the alignment mark in the exposure apparatus 200, and the components of the (N-1) order or less are obtained. And the coefficient of the higher-order component of the Nth order or higher of the above model formula acquired by the measuring device 100 may be used.

In the lithography system according to the second embodiment, when the measurement unit 40 of the measurement device 100 includes the above-mentioned multipoint focal position detection system, the measurement device 100 performs the wafer alignment measurement and the wafer W. Flatness measurement (also called focus mapping) may be performed. In this case, by using the result of the flatness measurement, it is possible to control the focus leveling of the wafer W at the time of exposure without performing the flatness measurement by the exposure apparatus 200.

In the second embodiment, the target is a 300 mm wafer, but the present invention is not limited to this, and a 450 mm wafer having a diameter of 450 mm may be used. Since the wafer alignment can be performed by the measuring device 100 separately from the exposure device 200, for example, all-point EGA measurement can be performed even with a 450 mm wafer without causing a decrease in the throughput of the exposure process.

Although not shown, the exposure device 200 and the C / D 300 may be connected in-line in the lithography system 1000, and the measurement device 100 may be arranged on the opposite side of the C / D 300 from the exposure device 200. In this case, the measuring device 100 can be used, for example, for the same alignment measurement (hereinafter, referred to as pre-measurement) as described above for a wafer before resist coating. Alternatively, the measuring device 100 can be used for the position deviation measurement (superimposition deviation measurement) of the above-mentioned overlay deviation measurement mark on the wafer after the development is completed, or can be used for the pre-measurement and the overlap deviation measurement.

In the lithography system 1000 of FIG. 8, only one measuring device 100 is provided, but a plurality of measuring devices, for example, two may be provided as in the following modification.

<< Modification example >>
FIG. 11 schematically shows the configuration of the lithography system 2000 according to the modified example. The lithography system 2000 includes an exposure device 200, a C / D 300, and two measuring devices 100a and 100b having the same configuration as the above-mentioned measuring device 100. The lithography system 2000 is installed in a clean room.

In the lithography system 2000, two measuring devices 100a and 100b are arranged in parallel between the exposure device 200 and the C / D 300.

The exposure devices 200, C / D 300, and the measuring devices 100a, 100b included in the lithography system 2000 have chambers arranged adjacent to each other. The exposure control device 220 of the exposure device 200, the coating development control device 320 of the C / D 300, and the control devices 60 of the measuring devices 100a and 100b are connected to each other via LAN 500 and communicate with each other. .. A storage device 400 is also connected to the LAN.

In the lithography system 2000 according to this modification, the same operation sequence as the lithography system 1000 described above can be set, so that the same effect as that of the lithography system 1000 can be obtained.

In addition to this, in the lithography system 2000, both of the measuring devices 100a and 100b are used for alignment measurement (hereinafter referred to as post-measurement) for the wafer after PB and for the wafer before resist coating. It is also possible to adopt a sequence used for alignment measurement (pre-measurement) similar to the above. In this case, since the pre-measurement for a certain wafer is performed in parallel with the above-mentioned series of wafer processing for a wafer different from the wafer, the throughput of the entire system is hardly reduced. However, for the first wafer, the pre-measurement time cannot overlap with the series of wafer processing times.

By comparing the position actually measured by the pre-measurement and the position actually measured by the post-measurement for the same wafer mark on the same wafer, the position measurement error of the wafer mark due to the resist coating can be obtained. Therefore, the position of the same wafer mark actually measured at the time of wafer alignment for the same wafer by the exposure apparatus 200 is corrected by the amount of the wafer mark position measurement error due to the resist coating obtained above, thereby applying the resist. Highly accurate EGA measurement is possible by canceling the measurement error of the wafer mark position due to the above.

In this case, in both the pre-measurement and the post-measurement, the measurement result of the position of the wafer mark is affected by the holding state of the wafer holder. It is desirable to adopt the sequence performed by 100b.

In the lithography system 2000, instead of the pre-measurement described above, the above-mentioned overlay deviation measurement for the wafer after the development may be performed. In this case, one of the predetermined measuring devices 100a and 100b may be dedicated to the post-measurement described above, and the other may be dedicated to the overlap misalignment measurement. Alternatively, for the same wafer, a sequence in which the post-measurement and the overlap misalignment measurement are performed by the same measuring device 100a or 100b may be adopted. In the latter case, the same wafer may be further pre-measured by the same measuring device.

Although not shown, in the lithography system 2000, a predetermined one of the measuring devices 100a and 100b, for example, the measuring device 100a may be arranged on the opposite side of the exposure device 200 of the C / D 300. In this case, the measuring device 100a is suitable for performing the above-mentioned overlay deviation measurement on the wafer after the development is completed, considering the flow of wafer transportation. If the individual difference in the holding state of the holder between the measuring devices 100a and 100b is not a problem, the measuring device 100a may be used for pre-measurement instead of the superposition misalignment measurement, or the superposition misalignment may be used. It may be used for measurement and pre-measurement.

In addition to the exposure device 200 and the C / D 300, three or more measuring devices 100 are provided, all the devices are connected in-line, and two of the three measuring devices 100 are measured in advance and afterwards. The remaining one measuring device may be dedicated to the overlap misalignment measurement. The former two may be dedicated to pre-measurement and post-measurement, respectively.

In the second embodiment and the modification, the signal processing device 49 that processes the detection signal of the mark detection system MDS included in the measuring devices 100, 100a, 100b is the detection obtained as the detection result of the mark detection system MDS. By sending only the measurement results of the wafer marks having a good signal waveform to the control device 60, the control device 60 performs the EGA calculation using the measurement results of those wafer marks, and as a result, the exposure control device is marked by 220. The case where the EGA calculation is performed using a part of the position information of the position information of the wafer mark selected from the plurality of wafer marks having a good waveform of the detection signal obtained as the detection result by the detection system MDS has been described. However, not limited to this, the signal processing device 49 sends the measurement result of the remaining wafer marks excluding the wafer mark having a defective waveform of the detection signal obtained as the detection result of the mark detection system MDS to the control device 60. May be. Further, the control device 60 may determine whether or not the detection signal obtained as the detection result by the mark detection system MDS is good instead of the signal processing device. In this case, the control device 60 also determines the detection signal. The above-mentioned EGA calculation is performed using only the measurement results of the wafer marks determined to be good or the remaining wafer marks excluding the wafer marks whose detection signal is determined to be defective. Then, it is desirable that the exposure control device 220 performs the above-mentioned EGA calculation using the measurement results of some wafer marks selected from the measurement results of the wafer marks used for the EGA calculation by the control device 60.

In the second embodiment and the modified example, the case where the measuring devices 100, 100a, 100b are arranged between the exposure device 200 and the C / D 300 instead of the in-line interface unit has been illustrated. The measuring device (100, 100a, 100b) may be a part of the exposure device. For example, the measuring device may be installed in the carry-in portion of the exposure device 200 into which the wafer before exposure is carried. Further, when the measuring device (100, 100a, 100b) is installed in the chamber of the exposure device 200 as a part of the exposure device 200, the measuring device may or may not include the chamber. .. When the measuring device (100, 100a, 100b) is a part of the exposure device, the measuring device may or may not be provided with a control device and is controlled by the control device of the exposure device without the control device. You may. In any case, the measuring device is connected in-line to the exposure device.

In the above embodiment, the case where the substrate processing apparatus is C / D has been described, but the substrate processing apparatus may be an apparatus connected in-line to the exposure apparatus and the measuring apparatus, and is sensitive to the substrate (wafer). It may be a coating device (coater) for applying an agent (resist), a developing device (developer) for developing a substrate (wafer) after exposure, or a coating device (developer) connected in-line to the exposure device and the measuring device, respectively. It may be a coater) and a developing device (developer).

When the substrate processing device is a coating device (coater), the measuring device can be used only for the above-mentioned post-measurement or for pre-measurement and post-measurement. In this case, the exposed wafer is carried into a developing device that is not connected in-line to the exposure device.

When the substrate processing device is a developing device (developer), the measuring device can be used only for the post-measurement described above, or for the post-measurement and the overlay misalignment measurement. In this case, the wafer to which the resist has been applied in advance at another place is carried into the exposure apparatus.

In the second embodiment and the modified example (hereinafter, referred to as the second embodiment and the like), the case where the exposure apparatus is a scanning stepper has been described, but the exposure apparatus is not limited to this, and the exposure apparatus may be a stepper or the like. It may be a static exposure apparatus, or it may be a step-and-stitch type reduction projection exposure apparatus that combines a shot area and a shot area. Further, as disclosed in, for example, U.S. Pat. Nos. 6,590,634, U.S. Pat. No. 5,969,441, U.S. Pat. No. 6,208,407, and the like, a plurality of wafers. The second embodiment and the like can be applied to a multi-stage type exposure apparatus provided with a stage. Further, the exposure apparatus is not limited to the dry type exposure apparatus that exposes the wafer W without using the liquid (water) described above, and is, for example, European Patent Application Publication No. 1420298, International Publication No. 2004/055803. , International Publication No. 2004/057590, U.S. Patent Application Publication No. 2006/0231206, U.S. Patent Application Publication No. 2005/0280791, U.S. Patent No. 6,952,253, etc. It may be a immersion type exposure apparatus that exposes the substrate through a liquid. Further, the exposure apparatus is not limited to the exposure apparatus for semiconductor manufacturing, and may be, for example, an exposure apparatus for liquid crystal that transfers a liquid crystal display element pattern onto a square glass plate.

In addition, all the publications, international publications, US patent application publication specifications, and disclosures of US patent specifications relating to the exposure apparatus and the like cited in the above-described embodiment are incorporated as a part of the description of this specification.

The semiconductor device is an exposure apparatus constituting the lithography system according to the above embodiment, and is manufactured through a lithography step of exposing a photosensitive object using a reticle (mask) on which a pattern is formed and developing the exposed photosensitive object. Will be done. In this case, a device having a high degree of integration can be manufactured with a high yield.

In addition to the lithography step, the semiconductor device manufacturing process includes a step of designing the function and performance of the device, a step of manufacturing a reticle (mask) based on this design step, and a device assembly step (dicing process, bonding process, etc.). (Including packaging process), inspection steps, etc. may be included.

10 ... slider, 12 ... platen, 14 ... vibration isolator, 16 ... base frame, 18 ... air bearing, 20 ... drive system, 20A ... first drive device, 20B ... second drive device, 22a, 22b ... mover , 23a, 23b ... Movable element, 24 ... Movable stage, 25a, 25b ... Stator, 26a, 26b ... Stator, 28A, 28B ... X-axis linear motor, 29A, 29B ... Y-axis linear motor, 30 ... First position Measurement system, 32 ... head unit, 33 ... encoder system, 35a to 35d ... laser interferometer, 37x ... X head, 37ya, 37yb ... Y head, 40 ... measurement unit, 48 ... vibration isolator, 50 ... second position measurement System, 52A, 52B ... Head unit, 58X ₁ , 58X ₂ ... XZ head, 58Y ₁ , 58Y ₂ ... YZ head, 60 ... Control device, 100 ... Measuring device, 100a, 100b ... Measuring device, 200 ... Exposure device, 300 ... C / D, 330 ... Temperature control unit, 1000 ... lithography system, MDS ... mark detection system, RG1 ... grating, RG2a, RG2b ... grating, W ... wafer, WST ... wafer stage.

Claims (24)

A measuring device that measures the position information of marks formed on a substrate.
A mark detection system that detects marks formed on the substrate, and
A stage that can hold and move the substrate,
A base member that movably supports the stage and
A first position measurement system that acquires the position information of the stage with respect to the base member, and
A second position measurement system that acquires relative position information between the base member and the mark detection system,
A detection system for acquiring height information of the substrate surface held on the stage is provided.
The position of the mark based on the position information of the stage acquired by the first position measurement system, the relative position information acquired by the second position measurement system, and the mark detection result detected by the mark detection system. A measuring device that acquires information. The measuring device according to claim 1, wherein the height information acquired by the detection system includes tilt information on the surface of the substrate. The relative position information acquired by the second position measurement system is used for correcting the position information of the mark calculated from the mark detection result by the mark detection system and the position information of the stage by the first position measurement system. The measuring device according to claim 1 or 2. The height information detected by the detection system is used for correcting the position information of the mark calculated from the mark detection result by the mark detection system and the position information of the stage by the first position measurement system. The measuring device according to any one of 3 to 3. The measuring device according to any one of claims 1 to 3, wherein the height information detected by the detection system is used for correcting target position information moving on the stage. The measuring device according to any one of claims 1 to 5, further comprising a driving device for moving the stage on the base member. The driving device produces a driving force in a first direction in which the stage is parallel to the surface of the substrate and a driving force in a second direction parallel to the surface of the substrate and orthogonal to the first direction. The measuring device according to claim 6, further comprising a second driving device to be generated, and moving the stage by the first driving device and the second driving device. The measuring device according to claim 7, wherein at least one of the first driving device and the second driving device generates a driving force in a third direction orthogonal to the first direction and the second direction. The drive device directs the stage in a first direction parallel to the surface of the substrate, a second direction parallel to the surface of the substrate and orthogonal to the first direction, and orthogonal to the first direction and the second direction. The measuring device according to claim 6, which is a flat motor that generates a driving force in a third direction. The measuring device according to any one of claims 1 to 9, wherein the detection system is a multipoint focal position detection system provided separately from the mark detection system. The measuring device according to any one of claims 1 to 10.
It has a substrate stage on which the substrate on which the measurement of the position information of the plurality of marks has been completed by the measuring device is placed, and a plurality of substrates on the substrate are mounted on the substrate stage. A lithography system including an alignment measurement for measuring the position information of a part of marks selected from the marks and an exposure apparatus for exposing the substrate with an energy beam. The lithography system according to claim 11, wherein some of the marks selected at the time of alignment measurement are a part of a plurality of marks whose position information has been measured by the measuring device. Claim 11 or 12 in which the movement of the substrate stage is controlled based on the position information of the plurality of marks obtained by the measuring device and the position information of the marks obtained by the alignment measurement in the exposure device. The lithography system described in. The lithography system according to any one of claims 11 to 13, further comprising a substrate processing apparatus for performing a predetermined process on the substrate. The lithography system according to claim 14, wherein the substrate processing apparatus is a coating apparatus for applying a sensitive agent on a substrate. The lithography system according to claim 15, wherein the substrate processing apparatus is a coating and developing apparatus that coats a sensitive agent on a substrate and develops the substrate after exposure. The lithography system according to claim 15 or 16, wherein the measuring device is used in pre-measurement for measuring position information of a plurality of marks on a substrate before the sensitive agent is applied. The lithography system according to claim 15 or 16, wherein the measuring device is used in post-measurement for measuring the position information of the plurality of marks on the substrate coated with the sensitive agent. A plurality of the measuring devices are provided,
The first measuring device and the second measuring device of the plurality of measuring devices are pre-measurement for measuring the position information of a plurality of marks on the substrate before the sensitive agent is applied, and the sensitive agent It is used in both post-measurement to measure the position information of the plurality of marks on the coated substrate.
The 15 or 16 according to claim 15 or 16, wherein the first measuring device and the second measuring device are both used in the pre-measurement and the post-measurement on the same substrate when continuously processing a plurality of substrates. Lithography system. A plurality of the measuring devices are provided,
The first measuring device among the plurality of measuring devices is used for post-measurement for measuring the position information of the plurality of marks on the substrate coated with the sensitive agent.
The lithography according to claim 15 or 16, wherein the second measuring device among the plurality of measuring devices is used for pre-measurement for measuring the position information of a plurality of marks on the substrate before the sensitive agent is applied. system. The measuring device is subjected to post-measurement for measuring the position information of the plurality of marks on the substrate coated with the sensitive agent, exposure processing by the exposure apparatus, and development processing by the substrate processing apparatus on the substrate. The lithography system according to claim 16, which is used in both the superposition deviation measurement for measuring the formed superposition deviation measurement mark. A plurality of the measuring devices are provided,
The first measuring device among the plurality of measuring devices is used in post-measurement for measuring the position information of the plurality of marks on the substrate coated with the sensitive agent.
The second measuring device among the plurality of measuring devices is used for the superposition deviation measurement for measuring the superposition deviation measurement mark formed on the substrate by the exposure processing by the exposure device and the development processing by the substrate processing device. The lithography system according to claim 16. The invention according to any one of claims 11 to 22, further comprising a temperature control device for controlling the temperature of the substrate so as to be within a predetermined temperature range prior to being mounted on the stage of the measuring device. Lithography system. To expose and develop a substrate using the lithography system according to any one of claims 11 to 23.
A device manufacturing method including dividing the substrate on which a device pattern is formed into a plurality of chips.

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